How to Design an Isolated, High Frequency, Push-Pull DC/DC Converter

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "How to Design an Isolated, High Frequency, Push-Pull DC/DC Converter"

Transcription

1 How to Design an Isolated, High Frequency, Push-Pull DC/DC Converter Dawson Huang A simple push-pull DC/DC converter with a fixed % duty cycle is often used as a low noise transformer driver in communication systems, medical instruments and distributed power supplies. This simple scheme provides no voltage regulation requiring a low dropout () post regulator a combination that presents potentially serious problems. First, any significant variation in the driver s input voltage, along with the fixed % duty cycle, can increase the differential voltage across the, resulting in significant power losses and high temperature rise in the. Second, low switching frequency requires relatively bulky transformers, sometimes occupying % to % of the converter space. The LT999 monolithic DC/DC push-pull driver avoids these issues with two important features: duty cycle control and high frequency operation: Duty cycle control allows compensation for wide variation something standard fixed duty cycle transformer drivers cannot do greatly reducing loss when facing a wide input range. High switching frequency, up to MHz, leads to smaller transformers and lower output ripple. The LT999 combines these two features with high V input voltage and A input current capabilities, making it a high power and flexible low noise push-pull converter IC. This article presents two step-bystep design procedures: One for a push-pull DC/DC converter with a wide input range, the other for a compact high frequency transformer driver with fixed input voltage. PUSH-PULL DC/DC CONVERTER DESIGN FOR WIDE RANGING INPUT The flowchart in Figure b shows how a push-pull converter can be designed in eight simple steps. These steps produce the LT999 V V input, ±V output, ma MHz pushpull converter shown in Figure a. Figure. LT999 push-pull DC/DC converter with wide input range and duty cycle control Easy -step push-pull converter design APPLICATION SPECIFICATIONS f SW, (MIN), (MAX), V OUT, I OUT, I OUT & (MIN) TO (MAX) R DC C IN R R CSS R R R BIAS SYNC RT ILIM/SS LT999 RBIAS GND SWA SWB R C T D D D D L C R D L C U POSITIVE U NEGATIVE V OUT C OUT V OUT C OUT R DC N N P :N S RECTIFIER INDUCTOR SNUBBER April : LT Journal of Analog Innovation

2 The LT999 is a monolithic DC/DC transformer driver, which features duty cycle control, high frequency and high power. It allows a wide input voltage range and low loss at the, while using small passive components due to the high frequency operation. It also features input voltage up to V and input current up to A. Step : Set the Switching Frequency ( ) First, set the switching frequency with ; the value chosen from Table in the LT999 data sheet..k sets f SW MHz. Step : Set the Input Voltage Range (, ) The (undervoltage lockout) and (overvoltage lockout/ duty cycle) pins are used to set input voltage range. Either a - or -resistor method can be used. For the -resistor method shown in Figure a, R B is calculated using equations and for and, respectively. For low loss, we can assume MΩ. For : For OVLO: R B OR R B( ) R B( OVLO) R B ( MIN). ( MAX). For the -resistor method shown in Figure b, and R B are Figure. Setting the precision and OVLO/ DC via resistor divider using either a -resistor method or a -resistor method. () () calculated by equations and for and, respectively. can be chosen around MΩ. ( MIN) ( MAX) ( MIN). R B ( MIN) ( MAX) ( MIN). For the -resistor method used in Figure a: (MIN) V, M, R B k. (MAX).V, M, R B.k. Step : Set the Maximum Duty Cycle (R DC(MAX) ) The maximum duty cycle (DC MAX ) is () () determined by the switching period (T S /f SW ) and non-overlap time (T D(MIN) ) between the two power switches, as shown in equation. For the -resistor method, R DC is calculated by equation. For the -resistor method, substitute + in equation. DC MAX TS TD(MIN) TS RB (MIN) DC MAX R + R A B. In the Figure example, T S µs, T D(MIN) ns (typical value in the data sheet), (MIN) V, M, () () R B k. Calculations and give DC MAX., and R DC.k. Step : Select the Transformer (T) The transformer turns ratio is represented in equation. N N s Np VOUT + VOUT + V+ V + VF VIN(MIN) V SW DCmax ( ) V SW is the switch saturation voltage for internal switches. V F is the forward voltage of the rectifier diodes. V and V are the dropout voltages of the positive and negative s. V SW.V, V F.V, V V.V are good rules of thumb. If a commercial transformer with an exact calculated turns ratio cannot be found, select one that is close and calculate DC MAX in equation accordingly. Then, recalculate R DC in equation based on new DC MAX. () In the Figure example, V OUT V OUT V and (MIN) V, so choose Wurth (N ) for DC MAX.. Step : Design the Rectifier (D, D, D and D) The peak voltage across the rectifier bridge is composed of the transformer secondary side voltage (V SEC ) plus any ringing voltage spikes. V SEC is calculated using equation. The ringing voltage spike, however, is difficult to predict, as it depends on the loop resistance, the leakage inductance of the transformer, and the junction capacitance of the rectifiers. As general rule, the rectifier voltage rating (V REC ) should be at April : LT Journal of Analog Innovation

3 I OUT I OUT ma. V. POWER LOSS.. POWER LOSS (W) POWER LOSS.. POWER LOSS (W) V DIFF. V DIFF. (V) I OUT I OUT (ma) Figure. (U) V OUT differential and power loss vs input voltage Figure. (U) V OUT differential and power loss vs load least. times the transformer turns ratio multiplied by the maximum input voltage. Because the two secondary windings are connected across the rectifier bridge, a factor of two is required, producing the formula for the rectifier voltage rating: VREC. N VIN(MAX) () The current rating of the rectifier (I REC ) should be greater than the load current. When (MAX).V, N, V REC 9V, I REC ma: a Central CMSH-HE (V, A) satisfies these requirements. Step : Select the Inductors (L, L) The minimum inductor value (L MIN ) is set by the peak current limit of internal switcher (I LIM ) as shown by equation 9. L MIN T N (MAX) ( DC MIN ) DC S MIN I LIM N I OUT (9) Higher inductance produces better regulation and lower voltage ripple, but requires a correspondingly greater volume part. The optimum inductor value is determined by taking into account both output noise and solution volume requirements. When (MAX).V, DC MIN., T S µs, N, I LIM A, I OUT I OUT ma, L MIN.µH: A Coilcraft XFL-9MEC (9.µH) satisfies these requirements without adding unnecessary size. Step : Select the Low Dropout Linear Regulator (U, U) The maximum voltage of occurs at maximum input voltage under no load, when V SEC equals (MAX) N. The current rating of the should be greater than the load current. When (MAX).V, N, the voltage rating for the s should be V and V, satisfied by the LT (V, ma) and LT9 ( V, ma), respectively. Step : Add a Snubber (C S and R S ) The recommended approach for designing an RC snubber (C S and R S in Figure ) is to measure the period of the ringing at the LT999 s SWA and SWB pins when its switchers turn off without the snubber, and then add capacitance starting with something in the range of pf until the ringing period lengthens by.x to x. The change in period determines the value of the parasitic capacitance (C PAR ), from which the parasitic inductance (L PAR ) can be determined from the initial period. Similarly, initial values can be estimated using data sheet values for switch capacitance and transformer leakage inductance. Once the value of the drain node capacitance and inductance are known, a series resistor can be added to the snubber capacitance to dissipate power and critically dampen the ringing. The equation for deriving the optimal series resistance using the observed periods (t PERIOD, and t PERIOD(SNUBBED) ) and snubber capacitance (C S ) is below. Refer to the LT data sheet for more details. CS CPAR () tperiod( SNUBBED) tperiod ( tperiod) LPAR () C PAR π LPAR RSNUBBER () CPAR RESULTS The measured results in Figures, and show that duty cycle control in the push-pull converter of Figure maintains a low V OUT differential across the s, resulting in minimized power loss and temperature rise. Figure shows that at ma per, V DIFF, remains under.v over the entire input voltage range of V V. Figure shows power loss remains low across the load current range. Figure and Figure show the thermal results. For comparison, Figure shows the efficiency comparison of the design with duty cycle control disabled and duty April : LT Journal of Analog Innovation

4 U T U U T U U U V V OUT V, V OUT V I OUT I OUT ma V V OUT V, V OUT V I OUT I OUT ma Figure. Thermal image of the design in Figure in action, V Figure. Thermal image, V cycle control enabled. The efficiency drops dramatically when input voltage increases. Figure shows the differential voltage across the positive with duty cycle control disabled and duty cycle control enabled. Figures 9 and show the thermal results. It is evident that the duty cycle control reduces the differential voltage and improves the efficiency and thermal performance COMPACT TRANSFORMER DRIVER FO FIXED INPUT VOLTAGE Normally, the output voltage of the basic unregulated transformer driver converter changes significantly with changes in load current. To produce a regulated voltage, an on the output is strongly recommended. Figure a shows the schematic of low part count transformer driver using the LT999. Figure b shows the design flowchart. The four simple steps in the flowchart can be used to design a MHz, low parts count, V input, V output ma output transformer driver as an example. Step : Set the Switching Frequency ( ) The switching frequency of the LT999 is set by a single resistor selected based on the table in the LT999 data sheet (frequency range is from khz to MHz). In the design example, for high frequency f SW MHz,.k. Step : Select the Transformer (T) The transformer turns ratio is determined by: + + N N S VOUT V(OPTIONAL) VF NP VIN VSW where V SW is the switch saturation voltage for internal switchers, and V F is the forward voltage of a rectifier diode. EFFICIENCY (%) ENABLED DISABLED (V) () V is the drop from the unregulated transformer driver output to the post regulated low noise output. V is the drop at highest current, so it should be minimized..v provides enough drop to avoid dropout without the getting hot. A good rule of thumb assumption is V SW.V, V F.V, V.V. The current rating of the transformer should be %~% larger than the output current to leave some room. The sum of the peak magnetizing current (I M(PEAK) ) and the full load current reflected to the primary side (N I OUT ) should less than the peak current limit of the internal switcher (I LIM ). Based on this, minimal L M (L M(MIN) ) is required. DISABLED ENABLED (V) Figure. Efficiency comparison of the design with duty cycle control disabled and duty cycle control enabled, I OUT I OUT ma Figure. (U) V OUT differential vs at full load with duty cycle control disabled and with duty cycle control enabled, I OUT I OUT ma April : LT Journal of Analog Innovation

5 U T U U T U U U V V OUT V, V OUT V I OUT I OUT ma V V OUT V, V OUT V I OUT I OUT ma Figure 9. Thermal image of the design with duty cycle control disabled in circuit of Figure, V Figure. Thermal image of the design with duty cycle control disabled in circuit of Figure, V IMPEAK ( ) + N IOUT V IN V SW T S + N IOUT LM < ILIM () VIN VSW L > T S M LM I N I ( MIN ) () LIM OUT For V OUT V, the Coilcraft PA-AL (N.) is a good fit. Step : Rectifier (D, D) Choose the rectifier diodes based on voltage and current. The voltage across the diodes is more than twice that of the transformer secondary voltage because of its center tap structure. The voltage rating of the rectifier should be larger than N V, maybe by %. The CMSH-M (V, A) satisfies these requirements. Step : Low Dropout Linear Regulator (U, Optional) The maximum input voltage of the optional post-regulating (V _IN(MAX) ) occurs at no load, where it equals N.V. The current rating of the should be larger than the load current (>ma in the case of the design example). A good for the V, ma output is the LT (V, ma). CONCLUSION The LT999 is a monolithic DC/DC transformer driver, which features duty cycle control, high frequency and high power. It allows a wide input voltage range and low loss at the, while using small passive components due to its high frequency operation. It also features input voltage up to V and input current up to A. n C IN R BIAS SYNC RT ILIM/SS LT999 RBIAS GND SWA SWB T D D C OUT OPTIONAL IN OUT IN C OUT V OUT APPLICATION SPECIFICATIONS f SW,, V OUT, I OUT N N P :N S RECTIFIER Figure. Low parts count, fixed input voltage transformer driver. Design flowchart for the transformer driver April : LT Journal of Analog Innovation 9

Power supplies. EE328 Power Electronics Assoc. Prof. Dr. Mutlu BOZTEPE Ege University, Dept. of E&E

Power supplies. EE328 Power Electronics Assoc. Prof. Dr. Mutlu BOZTEPE Ege University, Dept. of E&E Power supplies EE328 Power Electronics Assoc. Prof. Dr. Mutlu BOZTEPE Ege University, Dept. of E&E EE328 POWER ELECTRONICS Outline of lecture Introduction to power supplies Modelling a power transformer

More information

1.5MHz, 900mA Synchronous Step-Down Converter

1.5MHz, 900mA Synchronous Step-Down Converter 1.5MHz, 900mA Synchronous Step-Down Converter FEATURES High Efficiency - Up to 95% Guaranteed 900mA Output Current 2.5V to 5.5V Input Voltage Range 1.5MHz Constant Frequency Operation No external Schottky

More information

AEROSEMI MT3608 GENERAL DESCRIPTION FEATURES APPLICATIONS TYPICAL APPLICATION. High Efficiency 1.2MHz 2A Step Up Converter.

AEROSEMI MT3608 GENERAL DESCRIPTION FEATURES APPLICATIONS TYPICAL APPLICATION. High Efficiency 1.2MHz 2A Step Up Converter. FEATURES AEROSEMI Integrated 80mΩ Power MOSFET 2V to 24V Input Voltage 1.2MHz Fixed Switching Frequency Internal 4A Switch Current Limit Adjustable Output Voltage Internal Compensation Up to 28V Output

More information

STEP-DOWN SWITCHING VOLTAGE REGULATOR IN HERMETIC ISOLATED PACKAGE

STEP-DOWN SWITCHING VOLTAGE REGULATOR IN HERMETIC ISOLATED PACKAGE OM7 Series OMH7 Series STEP-DOWN SWITCHING VOLTAGE REGULATOR IN HERMETIC ISOLATED PACKAGE. Amp, V, V, V And Adjustable Voltage Versions In MO-78 Metal Package FEATURES Similar To Industry Standard LM7

More information

Welcome to the combined product training module of Linear Technology and Wurth Electronics about their efficient design solution for DC/DC Flyback

Welcome to the combined product training module of Linear Technology and Wurth Electronics about their efficient design solution for DC/DC Flyback Welcome to the combined product training module of Linear Technology and Wurth Electronics about their efficient design solution for DC/DC Flyback Converters. As leading manufacturers in their industries,

More information

SEMICONDUCTOR FC Pin Switch-Mode LED Lamp Driver IC FC9921 TECHNICAL DATA

SEMICONDUCTOR FC Pin Switch-Mode LED Lamp Driver IC FC9921 TECHNICAL DATA SEMICONDUCTOR TECHNICAL DATA FC99 3-Pin Switch-Mode LED Lamp Driver IC Features Constant output current: 0mA Universal 85-65VAC operation Fixed off-time buck converter Internal 475V power MOSFET Applications

More information

A Single Stage PFC+PWM Converter for W Distributed Power Systems

A Single Stage PFC+PWM Converter for W Distributed Power Systems A Single Stage PFCPWM Converter for 75-5 W Distributed Power Systems Dhaval Dalal and Olivier Meilhon, ON Semiconductor, USA dhaval.dalal@onsemi.com, olivier.meilhon@onsemi.com Abstract Many distributed

More information

Design and Construction of Variable DC Source for Laboratory Using Solar Energy

Design and Construction of Variable DC Source for Laboratory Using Solar Energy International Journal of Electronics and Computer Science Engineering 228 Available Online at www.ijecse.org ISSN- 2277-1956 Design and Construction of Variable DC Source for Laboratory Using Solar Energy

More information

Minimize Standby Current in Automotive DDR Supplies David Gilbert

Minimize Standby Current in Automotive DDR Supplies David Gilbert July 13 Volume 23 Number 2 I N T H I S I S S U E straighten out your power source priorities 8 µmodule DC/DC combines high efficiency switching with low noise linear regulation 18 reference clock distribution

More information

Absolute Maximum Ratings

Absolute Maximum Ratings RC15 Voltage-to-Frequency Converters www.fairchildsemi.com Features Single supply operation Pulse output DTL/TTL/CMOS compatible Programmable scale factor (K) High noise rejection Inherent monotonicity

More information

Reference Design for LCD TV LED Backlighting

Reference Design for LCD TV LED Backlighting Design Note DN06062/D Reference Design for LCD TV LED Backlighting Device Application Input Voltage Output Power NCP1294 LCD TV Back Lighting Topology I/O Isolation 24 V DC 25 W Flyback NONE DC Input Output

More information

Effects of High Switching Frequency on Buck Regulators

Effects of High Switching Frequency on Buck Regulators Effects of High Switching Frequency on Buck Regulators 1 Abstract The switching frequency is an operating parameter which affects nearly every performance characteristic of the supply, as well as the cost.

More information

FEB User s Guide 100W Power Factor Corrected Supply

FEB User s Guide 100W Power Factor Corrected Supply FEB112-001 User s Guide 100W Power Factor Corrected Supply Featured Fairchild Products: FAN7527B www.fairchildsemi.com/febsupport 2005 Fairchild Semiconductor Page 1 of 12 Rev 1.2 May 2005 Contents 1.

More information

LM5041 Application DC DC Converter Featuring the Cascaded Power Converter Topology

LM5041 Application DC DC Converter Featuring the Cascaded Power Converter Topology LM5041 Application DC DC Converter Featuring the Cascaded Power Converter Topology 1 Current Fed Push-Pull Concept Buck Stage Push-Pull Stage 33-76V Vout HB Vin HD HI HO HS LD LI LO LM5041 LM5101 Vss PUSH

More information

7-41 POWER FACTOR CORRECTION

7-41 POWER FACTOR CORRECTION POWER FTOR CORRECTION INTRODUCTION Modern electronic equipment can create noise that will cause problems with other equipment on the same supply system. To reduce system disturbances it is therefore essential

More information

MP2259 1A, 16V, 1.4MHz Step-Down Converter

MP2259 1A, 16V, 1.4MHz Step-Down Converter MP59 1A, 1V, 1.MHz Step-Down Converter TM The Future of Analog IC Technology DESCRIPTION The MP59 is a monolithic integrated stepdown switch mode converter with an internal power MOSFET. It achieves 1A

More information

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A-A ACTIVE RESET ISOLATED 48V INPUT TO DC/DC POWER CONVERTER

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A-A ACTIVE RESET ISOLATED 48V INPUT TO DC/DC POWER CONVERTER DESCRIPTION Demonstration circuit 1317A-A is isolated input to high current output 1/8th Brick footprint converter featuring the LT 1952 switching controller with Active Reset circuit. The Active Reset

More information

Two-Cell, Step-Up Converter Design for Portable Applications

Two-Cell, Step-Up Converter Design for Portable Applications Two-Cell, Step-Up Converter Design for Portable Applications James Liu Introduction In recent years, the markets for portable electrical devices, such as the electronic dictionary, palmtop computers, notebook

More information

LDS8720. 184 WLED Matrix Driver with Boost Converter FEATURES APPLICATION DESCRIPTION TYPICAL APPLICATION CIRCUIT

LDS8720. 184 WLED Matrix Driver with Boost Converter FEATURES APPLICATION DESCRIPTION TYPICAL APPLICATION CIRCUIT 184 WLED Matrix Driver with Boost Converter FEATURES High efficiency boost converter with the input voltage range from 2.7 to 5.5 V No external Schottky Required (Internal synchronous rectifier) 250 mv

More information

IC VOLTAGE REGULATORS

IC VOLTAGE REGULATORS IC VOLTAGE REGULATORS A voltage regulator is one of the most widely used electronic circuitry in any device. A regulated voltage (without fluctuations & noise levels) is very important for the smooth functioning

More information

Datasheet. 2A 380KHZ 20V PWM Buck DC/DC Converter. Features

Datasheet. 2A 380KHZ 20V PWM Buck DC/DC Converter. Features General Description Features The is a 380 KHz fixed frequency monolithic step down switch mode regulator with a built in internal Power MOSFET. It achieves 2A continuous output current over a wide input

More information

DC/DC Converter 9 to 36Vdc or 18 to 75 Vdc Input 3.3 to 15Vdc Single Outputs and ±5 to ±15Vdc Dual Outputs, 20W

DC/DC Converter 9 to 36Vdc or 18 to 75 Vdc Input 3.3 to 15Vdc Single Outputs and ±5 to ±15Vdc Dual Outputs, 20W TEN 20-WIN Series Application Note DC/DC Converter 9 to 36Vdc or 18 to 75 Vdc Input 3.3 to 15Vdc Single Outputs and ±5 to ±15Vdc Dual Outputs, 20W E188913 Complete TEN 20-WIN datasheet can be downloaded

More information

HIGH ISOLATION VOLTAGE FLYBACK TRANSFORMER

HIGH ISOLATION VOLTAGE FLYBACK TRANSFORMER HIGH ISOLATION VOLTAGE FLYBACK TRANSFORMER By: Edgar C. Taculog Field Application Engineer, Asia TT Electronics New TT Electronics AEC-Q200 qualified and certified transformers are optimized for use with

More information

LM2704 Micropower Step-up DC/DC Converter with 550mA Peak Current Limit

LM2704 Micropower Step-up DC/DC Converter with 550mA Peak Current Limit Micropower Step-up DC/DC Converter with 550mA Peak Current Limit General Description The LM2704 is a micropower step-up DC/DC in a small 5-lead SOT-23 package. A current limited, fixed off-time control

More information

LED Driver Switch-Mode LED Driver IC with High Current Accuracy L1 Q1 GATE R SC SC 4 OVP Q2 R T 7 FAULT FDBK C C COMP PWMD

LED Driver Switch-Mode LED Driver IC with High Current Accuracy L1 Q1 GATE R SC SC 4 OVP Q2 R T 7 FAULT FDBK C C COMP PWMD SEMICONDUCTOR TECHNICAL DATA FC9911 LED Driver Switch-Mode LED Driver IC with High Current Accuracy Features Switch mode controller for single switch drivers Buck Boost Buck-boost SEPIC Works with high

More information

Supertex inc. HV9910B. Universal High Brightness LED Driver. Features. General Description. Applications. Typical Application Circuit HV9910B

Supertex inc. HV9910B. Universal High Brightness LED Driver. Features. General Description. Applications. Typical Application Circuit HV9910B Universal High Brightness LED Driver Features Switch mode controller for single switch LED drivers Enhanced drop-in replacement to the HV9910 Open loop peak current controller Internal 8.0 to 450V linear

More information

DC/DC POWER CONVERSION TRANSFORMERS

DC/DC POWER CONVERSION TRANSFORMERS * Designed for use with Leading Controller Chips * Design Engineenring Support Available. * Provides DC/DC Conversion & Isolation * Multiple Configurations. GENERAL INFORMATION Premier Magnetics' Switch

More information

NMA 5V, 12V & 15V Series Isolated 1W Dual Output DC/DC Converters

NMA 5V, 12V & 15V Series Isolated 1W Dual Output DC/DC Converters www.murata-ps.com NMA 5V, 12V & 15V Series FEATURES RoHS compliant Efficiency up to 80% Power density up to 0.85W/cm 3 Wide temperature performance at full 1 Watt load, 40 C to 85 C Dual output from a

More information

Design of an Auxiliary Power Distribution Network for an Electric Vehicle

Design of an Auxiliary Power Distribution Network for an Electric Vehicle Design of an Auxiliary Power Distribution Network for an Electric Vehicle William Chen, Simon Round and Richard Duke Department of Electrical & Computer Engineering University of Canterbury, Christchurch,

More information

MEE1 Series Isolated 1W Single Output DC/DC Converters

MEE1 Series Isolated 1W Single Output DC/DC Converters www.murata-ps.com MEE1 Series FEATURES UL69 recognized Operation to zero load Single isolated output 1kVDC isolation Hi Pot Test Efficiency up to 87% typical Wide temperature performance at full 1 watt

More information

Over Current Protection IC With Shunt Regulator

Over Current Protection IC With Shunt Regulator Over Current Protection IC With Shunt Regulator FP133 General Description FP133 is a main rail current detection and over current protection IC. It includes a current shunt comparator and shutdown comparator

More information

TM MP2305 2A, 23V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER

TM MP2305 2A, 23V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER The Future of Analog IC Technology TM TM MP305 A, 3 Synchronous Rectified Step-Down Converter DESCRIPTION The MP305 is a monolithic synchronous buck regulator. The device integrates 30mΩ MOSFETS that provide

More information

Using voltage regulator to convert 5-12V range to 3.3V. Huan Lin

Using voltage regulator to convert 5-12V range to 3.3V. Huan Lin Using voltage regulator to convert 5-12V range to 3.3V Huan Lin 4/2/2010 1 Table of Contents 1. Introduction... Error! Bookmark not defined. 2. Objective... Error! Bookmark not defined. 3. Implementation...

More information

Buck Current/Voltage Fed Push-Pull PWM Controllers

Buck Current/Voltage Fed Push-Pull PWM Controllers Buck Current/Voltage Fed Push-Pull PWM Controllers UC1827-1/-2 FEATURES Ideal for Multiple Output and/or High Voltage Output Voltage Converters Up to 500kHz Operation High Voltage, High Current Floating

More information

Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan DS

Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan DS External NMOS Step-Down PWM Controller FEATURES N-Channel MOSFET Drive Operating Input Voltage from 4.5V to 24V Wide Ouput Range : 0.8V to 20V ±1.5% 0.8V Reference Low Dropout Operation : 95% Duty Cycle

More information

Designing a Low Power Flyback Power Supply

Designing a Low Power Flyback Power Supply APPLICATION NOTE INTRODUCTION Bourns is a well-known supplier of standard off-the-shelf high power inductors for power supplies in consumer, medical and automotive applications. Bourns also has a strong

More information

, and D 4.. Inductors L 1. and L 2

, and D 4.. Inductors L 1. and L 2 9.2.4 LinkSwitch-II isolated 4.2 LED driver Operation 644 Figure 3.269 provides the schematic for a universal input, 12 V, 350 ma CV/CC power supply using the LinkSwitch-II product LNK605DG (U1) in a flyback

More information

MP2365 3A, 28V, 1.4MHz Step-Down Converter

MP2365 3A, 28V, 1.4MHz Step-Down Converter The Future of Analog IC Technology MP365 3A, 8,.MHz Step-Down Converter DESCRIPTION The MP365 is a.mhz step-down regulator with a built-in Power MOSFET. It achieves 3A continuous output current over a

More information

LM5041 Cascaded PWM Controller

LM5041 Cascaded PWM Controller LM5041 Cascaded PWM Controller General Description The LM5041 PWM controller contains all of the features necessary to implement either current-fed or voltage-fed push-pull or bridge power converters.

More information

FAN5346 Series Boost LED Driver with PWM Dimming Interface

FAN5346 Series Boost LED Driver with PWM Dimming Interface FAN5346 Series Boost LED Driver with PWM Dimming Interface Features Asynchronous Boost Converter Drives LEDs in Series: FAN5346S20X: 20V Output FAN5346S30X: 30V Output 2.5V to 5.5V Input Voltage Range

More information

HV9931 Unity Power Factor LED Lamp Driver

HV9931 Unity Power Factor LED Lamp Driver Unity Power Factor LED Lamp Driver Initial Release Features Constant Output Current Large Step-Down Ratio Unity Power Factor Low Input Current Harmonic Distortion Fixed Frequency or Fixed Off-Time Operation

More information

UNIVERSAL HIGH-VOLTAGE LED DRIVER IL9910-A/B/C TECHNICAL DATA DESCRIPTION FEATURES APPLICATION ORDERING INFORMATIOIN

UNIVERSAL HIGH-VOLTAGE LED DRIVER IL9910-A/B/C TECHNICAL DATA DESCRIPTION FEATURES APPLICATION ORDERING INFORMATIOIN TECHNICAL DATA UNIVERSAL HIGH-VOLTAGE LED DRIVER IL9910-A/B/C DESCRIPTION The IL9910 is a PWM high-efficiency LED driver control IC. The IC is purposed for control of LED lighting as source of constant

More information

Series AMLDL-Z Up to 1000mA LED Driver

Series AMLDL-Z Up to 1000mA LED Driver FEATURES: Click on Series name for product info on aimtec.com Series Up to ma LED Driver Models Single output Model Input Voltage (V) Step Down DC/DC LED driver Operating Temperature range 4ºC to 85ºC

More information

Push-Pull FET Driver with Integrated Oscillator and Clock Output

Push-Pull FET Driver with Integrated Oscillator and Clock Output 19-3662; Rev 1; 5/7 Push-Pull FET Driver with Integrated Oscillator General Description The is a +4.5V to +15V push-pull, current-fed topology driver subsystem with an integrated oscillator for use in

More information

Half-Wave Rectifiers

Half-Wave Rectifiers Half-Wave Rectifiers Important Points of This Lecture Calculation of output voltage using appropriate piecewise models for diode for simple (unfiltered) half-wave rectifier Differences between calculations

More information

AND8328/D. 700 ma LED Power Supply Using Monolithic Controller and Off-Line Current Boosted (Tapped Inductor) Buck Converter

AND8328/D. 700 ma LED Power Supply Using Monolithic Controller and Off-Line Current Boosted (Tapped Inductor) Buck Converter 700 ma LED Power Supply Using Monolithic Controller and Off-Line Current Boosted (Tapped Inductor) Buck Converter Prepared by: Frank Cathell ON Semiconductor Introduction Light emitting diodes (LEDs) are

More information

AN SSL W flyback triac dimmable LED driver. Document information

AN SSL W flyback triac dimmable LED driver. Document information SSL2102 30 W flyback triac dimmable LED driver Rev. 01 10 October 2009 Application note Document information Info Keywords Abstract Content SSL2102, LED driver, mains dimmable, triac dimmer, flyback This

More information

PAM2841. Description. Pin Assignments. Features. Applications. Typical Applications Circuit. A Product Line of. Diodes Incorporated

PAM2841. Description. Pin Assignments. Features. Applications. Typical Applications Circuit. A Product Line of. Diodes Incorporated 1.5A SW CURRENT, 40V PRECISION WLED DRIVER Description Pin Assignments The is a white LED driver, capable of driving 10 or more WLEDs in series (depending on forward voltage of the LEDs) with a range of

More information

1.5A Very L.D.O Voltage Regulator LM29150/29151/29152

1.5A Very L.D.O Voltage Regulator LM29150/29151/29152 FEATURES High Current Capability 1.5A Low Dropout Voltage 350mV Low Ground Current Accurate 1% Guaranteed Initial Tolerance Extremely Fast Transient Response Reverse-Battery and "Load Dump" Protection

More information

Chapter 2 Application Requirements

Chapter 2 Application Requirements Chapter 2 Application Requirements The material presented in this script covers low voltage applications extending from battery operated portable electronics, through POL-converters (Point of Load), internet

More information

2A 380KHz 18V Buck DC to DC Converter

2A 380KHz 18V Buck DC to DC Converter Features Wide 3.6V to 18V Input Voltage Range Output Adjustable from 0.8V to 16V Maximum Duty Cycle 100% Minimum Drop Out 0.6V Fixed 380KHz Switching Frequency 2A Constant Output Current Capability Internal

More information

SELECTION GUIDE. Nominal Input

SELECTION GUIDE. Nominal Input www.murata-ps.com NKE Series FEATURES RoHS Compliant Sub-Miniature SIP & DIP Styles 3kVDC Isolation UL Recognised Wide Temperature performance at full 1 Watt load, 40 C to 85 C Increased Power Density

More information

CS8481. 3.3 V/250 ma, 5.0 V/100 ma Micropower Low Dropout Regulator with ENABLE

CS8481. 3.3 V/250 ma, 5.0 V/100 ma Micropower Low Dropout Regulator with ENABLE 3.3 /250 ma, 5.0 /100 ma Micropower Low Dropout Regulator with The CS8481 is a precision, dual Micropower linear voltage regulator. The switched 3.3 primary output ( OUT1 ) supplies up to 250 ma while

More information

UNIVERSITY of PENNSYLVANIA DEPARTMENT of ELECTRICAL and SYSTEMS ENGINEERING ESE206 - Electrical Circuits and Systems II Laboratory.

UNIVERSITY of PENNSYLVANIA DEPARTMENT of ELECTRICAL and SYSTEMS ENGINEERING ESE206 - Electrical Circuits and Systems II Laboratory. UNIVERSITY of PENNSYLVANIA DEPARTMENT of ELECTRICAL and SYSTEMS ENGINEERING ESE06 - Electrical Circuits and Systems II Laboratory. Objectives: Transformer Lab. Comparison of the ideal transformer versus

More information

Chapter 4. LLC Resonant Converter

Chapter 4. LLC Resonant Converter Chapter 4 LLC Resonant Converter 4.1 Introduction In previous chapters, the trends and technical challenges for front end DC/DC converter were discussed. High power density, high efficiency and high power

More information

Dual High Speed, Implanted BiFET Op Amp AD644

Dual High Speed, Implanted BiFET Op Amp AD644 a FEATURES Matched Offset Voltage Matched Offset Voltage Over Temperature Matched Bias Currents Crosstalk 124 db at 1 khz Low Bias Current: 35 pa max Warmed Up Low Offset Voltage: 500 V max Low Input Voltage

More information

Thermoelectric Generator power supply

Thermoelectric Generator power supply Thermoelectric Generator power supply Supervisor: Prof. Shmuel (Sam) Ben-Yaakov Students: Mark Pesah, Noa Levy Abstract: The main motivation for this project is the growing awareness for necessity of alternative

More information

AN1489 Application note

AN1489 Application note Application note VIPower: non isolated power supply using VIPer20 with secondary regulation Introduction Output voltage regulation with adjustable feedback compensation loop is very simple when a VIPer

More information

Properties of electrical signals

Properties of electrical signals DC Voltage Component (Average voltage) Properties of electrical signals v(t) = V DC + v ac (t) V DC is the voltage value displayed on a DC voltmeter Triangular waveform DC component Half-wave rectifier

More information

An9931. An9931 Unity Power Factor LED Lamp Driver

An9931. An9931 Unity Power Factor LED Lamp Driver An9931 Unity Power Factor LED Lamp Driver Features Constant output current Large step-down ratio Unity power factor Low input current harmonic distortion Fixed frequency or fixed off-time operation Internal

More information

L296 L296P HIGH CURRENT SWITCHING REGULATORS

L296 L296P HIGH CURRENT SWITCHING REGULATORS L296 L296P HIGH CURRENT SWITCHING REGULATORS 4 A OUTPUT CURRENT 5.1 V TO 40 V OUTPUT VOLTAGE RANGE 0 TO 100 % DUTY CYCLE RANGE PRECISE (±2 %) ON-CHIP REFERENCE SWITCHING FREQUENCY UP TO 200 KHz VERY HIGH

More information

LM5001 High Voltage Switch Mode Regulator

LM5001 High Voltage Switch Mode Regulator High Voltage Switch Mode Regulator General Description The LM5001 high voltage switch mode regulator features all of the functions necessary to implement efficient high voltage Boost, Flyback, SEPIC and

More information

A Novel Switched-Coupled-Inductor DC DC Step-Up Converter and Its Derivatives. Abstract

A Novel Switched-Coupled-Inductor DC DC Step-Up Converter and Its Derivatives. Abstract A Novel Switched-Coupled-Inductor DC DC Step-Up Converter and Its Derivatives Abstract Introduction: Various converters for high step-up applications has included the analysis of the switched-inductor

More information

TDA4605 CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS

TDA4605 CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS Fold-Back Characteristic provides Overload Protection for External Diodes Burst Operation under Short-Circuit and no Load Conditions

More information

National Semiconductor Power Products - Seminar 3 (LED Lighting)

National Semiconductor Power Products - Seminar 3 (LED Lighting) National Semiconductor Power Products - Seminar 3 (LED Lighting) Dr. Iain Mosely Converter Technology Ltd. Slide 1 Overview Background on LEDs Power Electronics for Driving LEDs LED Driver Specific Solutions

More information

SP1937. DC-DC Step-Up Converter for White LED. Battery Power Equipment Notebook Computers PDA Cellular Phone Digital Cameras MP3 Players GPS Receivers

SP1937. DC-DC Step-Up Converter for White LED. Battery Power Equipment Notebook Computers PDA Cellular Phone Digital Cameras MP3 Players GPS Receivers DESCRIPTION The SP1937 is a step-up DC/DC converter for white LED driver with constant current. The device can driver one to four LEDs in series from a single cell Lithium Ion battery. Internal functions

More information

Design Considerations for an LLC Resonant Converter

Design Considerations for an LLC Resonant Converter Design Considerations for an LLC Resonant Converter Hangseok Choi Power Conversion Team www.fairchildsemi.com 1. Introduction Growing demand for higher power density and low profile in power converter

More information

" PCB Layout for Switching Regulators "

 PCB Layout for Switching Regulators 1 " PCB Layout for Switching Regulators " 2 Introduction Linear series pass regulator I L V IN V OUT GAIN REF R L Series pass device drops the necessary voltage to maintain V OUT at it s programmed value

More information

Introduction to Push-Pull and Cascaded Power Converter Topologies

Introduction to Push-Pull and Cascaded Power Converter Topologies Introduction to Push-Pull and Cascaded Power Converter Topologies Bob Bell Principal Applications Engineer July 10, 2003 1 Good Morning! Welcome to National Semiconductor s continuing series of ON-Line

More information

PAM2804. Pin Assignments. Description. Applications. Features. Typical Applications Circuit 1A STEP-DOWN CONSTANT CURRENT, HIGH EFFICIENCY LED DRIVER

PAM2804. Pin Assignments. Description. Applications. Features. Typical Applications Circuit 1A STEP-DOWN CONSTANT CURRENT, HIGH EFFICIENCY LED DRIVER 1A STEP-DOWN CONSTANT CURRENT, HIGH EFFICIENCY LED DRIER Description Pin Assignments The is a step-down constant current LED driver. When the input voltage is down to lower than LED forward voltage, then

More information

CAT4139. 22 V High Current Boost White LED Driver

CAT4139. 22 V High Current Boost White LED Driver 22 V High Current Boost White LED Driver Description The CAT4139 is a DC/DC step up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a fixed switching frequency

More information

Miniature, 2W Isolated UNREGULATED DC/DC CONVERTERS

Miniature, 2W Isolated UNREGULATED DC/DC CONVERTERS Series For most current data sheet and other product information, visit www.burr-brown.com Miniature, W Isolated UNREGULATED DC/DC CONVERTERS FEATURES UP TO 89% EFFICIEY THERMAL PROTECTION DEVICE-TO-DEVICE

More information

TS321 Low Power Single Operational Amplifier

TS321 Low Power Single Operational Amplifier SOT-25 Pin Definition: 1. Input + 2. Ground 3. Input - 4. Output 5. Vcc General Description The TS321 brings performance and economy to low power systems. With high unity gain frequency and a guaranteed

More information

TOP VIEW 16 ON OUTPUT 3.3V/5V C3 SO

TOP VIEW 16 ON OUTPUT 3.3V/5V C3 SO 19-1254; Rev 0; 7/97 EALUATION KIT MANUAL FOLLOWS DATA SHEET 3.3/5 or Adjustable, General Description The integrate a step-up DC-DC converter with a linear regulator to provide step-up/down voltage conversion.

More information

TOPOLOGIES FOR SWITCHED MODE POWER SUPPLIES

TOPOLOGIES FOR SWITCHED MODE POWER SUPPLIES TOPOLOGIES FOR SWITCHED MODE POWER SUPPLIES by L. Wuidart I INTRODUCTION This paper presents an overview of the most important DC-DC converter topologies. The main object is to guide the designer in selecting

More information

Designers Series XII. Switching Power Magazine. Copyright 2005

Designers Series XII. Switching Power Magazine. Copyright 2005 Designers Series XII n this issue, and previous issues of SPM, we cover the latest technologies in exotic high-density power. Most power supplies in the commercial world, however, are built with the bread-and-butter

More information

Discrete Power IC Solutions For EPOS

Discrete Power IC Solutions For EPOS Fitipower Promotion Introduction of EPOS Barcode Scanner Portable Ordering Machine Marketing Department 2016-Q1 Mail:sam.wu@fitipower.com Phone:886-932285025 TME: 吳清順 1 Discrete Power IC Solutions For

More information

LM118/LM218/LM318 Operational Amplifiers

LM118/LM218/LM318 Operational Amplifiers LM118/LM218/LM318 Operational Amplifiers General Description The LM118 series are precision high speed operational amplifiers designed for applications requiring wide bandwidth and high slew rate. They

More information

DESCRIPTION FEATURES. LT1166 Power Output Stage Automatic Bias System APPLICATIONS TYPICAL APPLICATION

DESCRIPTION FEATURES. LT1166 Power Output Stage Automatic Bias System APPLICATIONS TYPICAL APPLICATION LT Power Output Stage Automatic Bias System FEATURES Set Class AB Bias Currents Eliminates Adjustments Eliminates Thermal Runaway of I Q Corrects for Device Mismatch Simplifies Heat Sinking Programmable

More information

AN4829 Application note

AN4829 Application note Application note Fishbone diagrams for a forward converter Rosario Costanzo, Antonino Gaito Introduction The purpose of this application note is to highlight all of the critical conditions affecting power

More information

Evaluating AC Current Sensor Options for Power Delivery Systems

Evaluating AC Current Sensor Options for Power Delivery Systems Evaluating AC Current Sensor Options for Power Delivery Systems State-of-the-art isolated ac current sensors based on CMOS technology can increase efficiency, performance and reliability compared to legacy

More information

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors.

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors. LM 358 Op Amp S k i l l L e v e l : I n t e r m e d i a t e OVERVIEW The LM 358 is a duel single supply operational amplifier. As it is a single supply it eliminates the need for a duel power supply, thus

More information

MIC4575. Features. General Description. Applications. Typical Application. 200kHz Simple 1A Buck Regulator

MIC4575. Features. General Description. Applications. Typical Application. 200kHz Simple 1A Buck Regulator 00kHz Simple 1A Buck Regulator General Description The is a series of easy to use fixed and adjustable BiCMOS step-down (buck) switch-mode voltage regulators. The 00kHz duplicates the pinout and function

More information

MP1541 1.3MHz Boost Converter

MP1541 1.3MHz Boost Converter MP5.3MHz Boost Converter The Future of Analog IC Technology DESCRIPTION The MP5 is a 5-pin thin SOT3 current mode step up converter intended for small, low power applications. The MP5 switches at.3mhz

More information

ELM621LA High efficiency 30V step up DC/DC converter

ELM621LA High efficiency 30V step up DC/DC converter General description ELM621LA is a high efficiency step-up DC/DC converter using a constant frequency, current mode architecture. Featuring current-mode and fixed frequency operation, this device incorporates

More information

Description. 5k (10k) - + 5k (10k)

Description. 5k (10k) - + 5k (10k) THAT Corporation Low Noise, High Performance Microphone Preamplifier IC FEATURES Excellent noise performance through the entire gain range Exceptionally low THD+N over the full audio bandwidth Low power

More information

Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers

Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers TECHNICAL DATA Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers IK3051 Description IK3051 is a highly integrated solution for SMPS applications requiring constant voltage

More information

Preliminary Datasheet

Preliminary Datasheet Features Macroblock Preliminary Datasheet 1.2A Constant Output Current 93% Efficiency @ input voltage 13V, 350mA, 9~36V Input Voltage Range Hysteretic PFM Improves Efficiency at Light Loads Settable Output

More information

LM1084 5A Low Dropout Positive Regulators

LM1084 5A Low Dropout Positive Regulators 5A Low Dropout Positive Regulators General Description The LM1084 is a series of low dropout voltage positive regulators with a maximum dropout of 1.5 at 5A of load current. It has the same pin-out as

More information

IS31LT3360 HB LED Driver General Evaluation Board Guide Quick Start

IS31LT3360 HB LED Driver General Evaluation Board Guide Quick Start Quick Start Description The IS31LT3360 is a continuous mode inductive step-down converter, designed for driving a single LED or multiple series connected LEDs efficiently from a voltage source higher than

More information

Introduction to Power Supplies

Introduction to Power Supplies Introduction to Power Supplies INTRODUCTION Virtually every piece of electronic equipment e g computers and their peripherals calculators TV and hi-fi equipment and instruments is powered from a DC power

More information

LM2576R. 3.0A, 52kHz, Step-Down Switching Regulator FEATURES. Applications DESCRIPTION TO-220 PKG TO-220V PKG TO-263 PKG ORDERING INFORMATION

LM2576R. 3.0A, 52kHz, Step-Down Switching Regulator FEATURES. Applications DESCRIPTION TO-220 PKG TO-220V PKG TO-263 PKG ORDERING INFORMATION LM2576 FEATURES 3.3, 5.0, 12, 15, and Adjustable Output ersions Adjustable ersion Output oltage Range, 1.23 to 37 +/- 4% AG10Maximum Over Line and Load Conditions Guaranteed 3.0A Output Current Wide Input

More information

FPAB20BH60B PFC SPM 3 Series for Single-Phase Boost PFC

FPAB20BH60B PFC SPM 3 Series for Single-Phase Boost PFC FPAB20BH60B PFC SPM 3 Series for Single-Phase Boost PFC Features UL Certified No. E209204 (UL1557) 600 V - 20 A Single-Phase Boost PFC with Integral Gate Driver and Protection Very Low Thermal Resistance

More information

SELF-OSCILLATING HALF-BRIDGE DRIVER V OFFSET. Packages

SELF-OSCILLATING HALF-BRIDGE DRIVER V OFFSET. Packages Preliminary Data Sheet No. PD60062K SELFOSCILLATING HALFBIDGE DIVE Features Integrated 600V halfbridge gate driver 15.6V zener clamp on Vcc True micropower start up Tighter initial deadtime control Low

More information

Designing DC/DC Converters to Meet CCITT Specifications for ISDN Terminals

Designing DC/DC Converters to Meet CCITT Specifications for ISDN Terminals Designing DC/DC Converters to Meet CCITT Specifications for ISDN Terminals AN704 Integrated Services Digital Network (ISDN) standards are a major step towards the realization of a worldwide information

More information

Offiline Step- down Buck LED Driver IC

Offiline Step- down Buck LED Driver IC General Description The is a high precision non-isolated buck driver IC, specially designed for universal input offline constant current LED lighting, and reach out low THD. Operating in critical conduction

More information

TDA2040. 20W Hi-Fi AUDIO POWER AMPLIFIER

TDA2040. 20W Hi-Fi AUDIO POWER AMPLIFIER 20W Hi-Fi AUDIO POWER AMPLIFIER DESCRIPTION The TDA2040 is a monolithic integrated circuit in Pentawatt package, intended for use as an audio class AB amplifier. Typically it provides 22W output power

More information

Why use a BJT in a flyback converter?

Why use a BJT in a flyback converter? Why use a BJT in a flyback converter? Michael O Loughlin, Senior Systems Solutions Engineer, Texas Instruments - March 30, 2014 In many low-power applications such as USB adaptors, cell phone chargers,

More information

Power Supplies. 1.0 Power Supply Basics. www.learnabout-electronics.org. Module

Power Supplies. 1.0 Power Supply Basics. www.learnabout-electronics.org. Module Module 1 www.learnabout-electronics.org Power Supplies 1.0 Power Supply Basics What you ll learn in Module 1 Section 1.0 Power Supply Basics. Basic functions of a power supply. Safety aspects of working

More information

L A STEP DOWN SWITCHING REGULATOR L4971

L A STEP DOWN SWITCHING REGULATOR L4971 L4971 1.A STEP DOWN SWITCHING REGULATOR UP TO 1.A STEP DOWN CONVERTER OPERATING INPUT VOLTAGE FROM 8V TO V PRECISE 3.3V (±1%) INTERNAL REFER- ENCE VOLTAGE OUTPUT VOLTAGE ADJUSTABLE FROM 3.3V TO V SWITCHING

More information