D365A Electroluminescent Lamp Driver IC

Transcription

1 Durel Division W. Chandler Blvd. Chandler, AZ - Tel:.9. / FAX: DA lectroluminescent amp Driver IC Data Sheet Features Integrated ow Noise Circuitry High AC Voltage Output Circuit Topology Shields MI Drives up to in amp Capacitor or xternal Clock F Control Available in ead-free (Pb-free) and Green MSOP- package Applications Cellular Phones and Handsets Monochrome CDs Data Organizer / PDAs Remote Controls DFX TM Keypad amps MSOP- Rogers DUR DA IC driver is part of a family of highly integrated drivers based on Rogers patented three-port (P) topology which offers built-in MI shielding. The DA IC and three components make a complete lamp driving circuit. quipped with a patented discharge circuitry, the DA IC device offers low-noise performance in applications that are sensitive to audible and electrical noise. amp Driver Specifications: (Using Standard Test Circuit at Ta= C unless otherwise specified.) Parameter Symbol Minimum Typical Maximum Units Conditions Standby Current na = Supply Current I ma = nable Current ua na Output Voltage Vout Vpp = amp Frequency F Hz = Inductor Frequency HF 9. khz = = = Standard Test Circuit mh DCR = Ω MMBTA pnp SMT. V BAS oad B. nf. µ F. V DA IT-I9 Rev A Page of

2 oad B* Typical Output Waveform nf Ω nf kω * oad B approximates a in (.cm ) lamp. Absolute Maximum Ratings: Parameter Symbol Minimum Maximum Unit Comments Supply voltage Operating Range Withstand Range nable voltage -. () +. V V = = amp Output Voltage V peak V Positive peak Voltage Power Dissipation Pd mw Operating Temperature T a - C Storage temperature T s - C Note: The above table reflects ratings only. Functional operation of the device at these ratings or any other above those indicated in the specifications is not implied. xposure to absolute maximum rating conditions for extended periods of time may affect reliability. Physical Data: PIN # NAM FUNCTI Positive input to inductor Base PNP transistor base connection High Frequency oscillator capacitor/clock input DC power supply input System enable; HI=On System ground connection Vout AC output to amp Negative input to inductor IT-I9 Rev A Page of

3 Typical Performance Characteristics Using Standard Test Circuit F (Hz) DC Input Voltage (V) Output Frequency vs. DC Supply Voltage F (Hz) - Temperature (ºC) Output Frequency vs. Ambient Temperature Output Voltage (Vpp) DC Input Voltage (V) Output Voltage vs. DC Supply Voltage Output Voltage (Vpp) - Temperature (ºC) Output Voltage vs. Ambient Temperature Avg Supply Current (m A) DC Input Voltage (V) Supply Current vs. DC Supply Voltage Avg Supply Current (ma) - Temperature (ºC) Supply Current vs. Ambient Temperature IT-I9 Rev A Page of

4 Block Diagram of the Inverter Circuitry. µf Base Divide by Discharger High Frequency Oscillator amp Theory of Operation lectroluminescent () lamps are essentially capacitors with one transparent electrode and a special phosphor material in the dielectric. The phosphor glows when a strong AC voltage is applied across the lamp electrodes. The required AC voltage is typically not present in most systems and must be generated from a low voltage DC source. Rogers developed its patented three-port (P) switch-mode inverter circuit to convert the available DC supply to an optimal drive signal for high brightness and lownoise lamp applications. Rogers P topology offers the simplicity of a single DC input, single AC output, and a shared common ground that provides an integrated MI shielding The DA IC drives the lamp by repeatedly pumping charge through an external inductor with current from a DC source and discharging into the capacitance of the lamp load. With each high frequency (HF) charging cycle the voltage on the lamp is increased. After HF charging cycles, the lamp voltage is discharged to ground in the period of HF cycles. Then, the polarity of the inductive charging is reversed, and the charging and discharging cycles are repeated. By this means, a low frequency (F) alternating positive and negative voltage is developed at the single output lead of the device to one of the electrodes of the lamp. Commonly connected to ground, the other lamp electrode can then be considered as electrical shielding for any underlying circuitry in the application. The driving system is divided into several parts: on-chip logic and control, on-chip high voltage output circuitry, discharge logic circuitry, and off-chip components. The on-chip logic controls the lamp operating frequency (F) as well as the inductor switching frequency (HF), and the HF and F duty cycles. These signals are combined and buffered to drive the high voltage output circuitry. The output circuitry handles the power through the inductor and delivers the high voltage to the lamp. The integrated discharge logic circuit enables the low-noise functionality of this driver. The selection of off-chip components provides a degree of flexibility to accommodate various lamp sizes, system voltages, and brightness levels. Since a key objective of driver systems is to save space and cost, required off-chip components are kept to a minimum. Rogers also provides a DA IC Designer s Kit, which includes a PC board intended to aid you in developing an lamp driver configuration that meets your requirements using the DA IC. A section on designing with the DA IC is included in this datasheet to serve as a guide to help you select the appropriate external components to complete your DA driver system. Typical DA IC configurations for driving lamps in various applications are shown below. The expected system outputs, such as lamp luminance; lamp output frequency and voltage; and average supply current draw for the various circuit configurations are also shown with each respective figure. IT-I9 Rev A Page of

5 Typical DA Driver Configurations.V Handset CD. mh Coilcraft DSB Typical Output uminance =. f (. cd/m ) amp Frequency = Hz Supply Current = ma Vout = Vpp oad: in (.9 cm ) DUR Green. nf. µf MMBTA pnp SMT. V. V BAS in DA D amp.v Handset CD + Keypad Typical Output uminance =. f (. cd/m ) amp Frequency = 9 Hz Supply Current = ma Vout = Vpp oad: in (. cm ) DUR Green MMBTA pnp SMT. V khz CK, % Duty BAS in. mh Sumida CS- amp. µf. V DA.V CD Backlight Typical Output uminance =. f (. cd/m ) amp Frequency = Hz Supply Current = ma Vout = 9 Vpp oad: in (. cm ) DUR Green MMBTA pnp SMT. V BAS in. mh Bujeon BDS-S amp. nf. µf. V DA IT-I9 Rev A Page of

6 Designing with A DA IC Driver I. amp Frequency Capacitor () Selection Selecting the appropriate value of capacitor will specify the inductor switching frequency (HF) and the lamp frequency (F) of the DA IC driver. A divider circuit in the internal oscillator circuitry of the DA IC divides the inductor switching frequency by to get the lamp frequency (F = HF/). amp frequencies of Hz are typically used for longer lamp life. Figure graphically represents the effect of capacitor value on the lamp frequency oscillator at =.V. In this example at =.V, F = nf-hz/. amp Frequency (Hz) (nf) Figure : Typical amp Frequency vs. CF Capacitor Alternatively, a high frequency clock input may be connected to the pin of the DA IC to specify the output driver frequency. The internal oscillator circuitry in the DA IC divides the input clock frequency by to get the output frequency. Therefore, for example, to get a Hz lamp frequency from a DA IC, the input clock signal must be khz. The selection of the capacitor value can also affect the brightness of the lamp because of its control of F and HF. Although input voltage and lamp size can change lamp frequency as well, F mainly depends on the value selected or the frequency of the input clock signal to. Figure shows typical brightness of a DA IC circuit with respect to lamp frequency on different lamp sizes. In this example, the supply voltage and inductor values were kept constant while only varying frequency. 9 amp Frequency (Hz) in in in Figure : uminance vs. amp Frequency ( =.V, DUR Green amps) IT-I9 Rev A Page of

7 II. Inductor () Selection The external inductor () selection for a DA IC circuit greatly affects the output capability and current draw of the driver. A careful designer will balance current draw considerations with output performance in the choice of an ideal inductor for a particular application. Figures and show typical brightness and current draw of a DA IC circuit with different inductor values, lamp sizes, and supply voltages. Please note that the DC resistance (DCR) of inductors with the same nominal inductance value may vary with manufacturer and inductor type. Therefore, inductors made by a different manufacturer may yield different outputs, but the trend of the different curves should be similar. amp luminance is also a function of lamp size. In each example, a larger lamp will have less luminance with approximately the same current draw. uminance (f) uminance Current Inductor (mh) Figure : uminance and current vs. inductor value. (Conditions: =.V, in amp) Current (ma) uminance (f) uminance Current Inductor (mh) Figure : uminance and current vs. inductor value. (Conditions: =.V, in amp) Current (ma) IT-I9 Rev A Page of

8 III. PNP Transistor Selection The DA IC requires an external PNP transistor to complete the high voltage P circuitry. Ideally, this transistor should have a minimum collector-emitter breakdown voltage higher than the required peak voltage output of the driver. It should also have a high DC current gain (>) and fast switching characteristics. Rogers typically recommends the MMBTA surface mount amplifier transistor for general purpose because it is a standard device part number supplied by several large manufacturers. The MMBTA has a breakdown voltage that is normally above V although it has a minimum rating of V only. The counterpart internal NPN transistor in the DA IC has a minimum V breakdown, with typical breakdown value above V. Under most nominal design considerations using the DA IC, the MMBTA is an appropriate selection. Nevertheless, caution is advised to limit designs well within the maximum output voltage ratings of all devices to avoid failure of the IC or any required external components. DA IC Design Ideas I. Alternate amp Connection In some applications it may be more convenient to connect the lamp to the supply voltage rather than ground. This type of connection (shown below) provides design flexibility and does not degrade driver performance. This configuration may also be used to minimize any positive DC bias on the lamp. BAS amp capacitor DA. µ F IT-I9 Rev A Page of

9 II. Driving Multi-segment amps The DA IC may be used to drive multiple lamp segments. An external transistor switching circuit is used to turn each lamp segment on or off independently or simultaneously. A high signal at the corresponding input will enable the corresponding lamp segment. In this configuration, amp is always turned on when the IC is enabled. Otherwise, always make sure that at least one lamp segment is selected to be on when the DA IC is enabled. BAS capacitor. µf DA amp Segment amp Segment amp Segment BAST MMBTT.K.K BAST BAST MMBTT MMBTT.K.K BAST MMBTT K nf K nf III. amp Frequency Control with an xternal Clock Signal An external clock signal may be used to control the inductor oscillating frequency (HF) and, consequently, the lamp frequency (F) of the DA IC. HF and F can be varied to synchronize the driver with other elements in the application. An internal divider network in the IC creates a ratio of HF/F=..V Min.V Max HF CK % +Duty. µ F BAS DA amp IT-I9 Rev A Page 9 of

10 IV. Controlling Brightness through Clock Pulse Width Modulation Pulse-width modulation of an external clock signal that controls the inductor oscillating frequency may also be used to regulate the brightness of an lamp. In this circuit, when the positive duty cycle of the external clock is at %, the lamp is at full brightness. Incremental dimming occurs as the positive duty cycle is increased to as high as %. This scheme may also be used inversely to regulate lamp brightness over the life of the battery or to compensate for lamp aging. In these cases, positive duty cycle may be incrementally increased as part of a feedback control in the application. (Note: Operation at duty cycles higher than % or lower than % is not recommended.).v Min.V Max HF CK BAS DA amp. µ F V. Two-evel Dimming Control Two level dimming may be achieved, as captioned in the example shown below. When DIM is low, the external PNP transistor is saturated and the lamp runs at full brightness. When DIM is high, the external PNP turns off and the Ω resistor reduces the voltage at () and dims the lamp. BAS amp capacitor. µ F DA Ω N9 kω DIM V bat IT-I9 Rev A Page of

11 VI. High Brightness through Supply Voltage Doubling An external voltage boost circuit may be used to increase the voltage supplied to the DA IC. In the following example, the M is used as a positive voltage doubler. capacitor BAS DA amp N Vin SD CAP+ OSC uf uf V uf CAP- M OUT VII. amp Output Regulation Regulating the DC supply input voltage to the DA IC will result in a constant brightness level from the lamp, regardless of battery voltage. In this example, a voltage regulator is used. BAS amp capacitor. µf DA OUT MIC IN Vbat IT-I9 Rev A Page of

12 XIII. Solder Re-Flow Recommendations Classification Reflow Profiles Sn-Pb utectic Assembly Pb-Free Assembly Profile Feature arge Body Small Body arge Body Small Body Average ramp-up rate (T to T P ) Preheat -Temperature Min (Ts min ) -Temperature Max (Ts max ) -Time (min to max) (ts) Ts max to T -Ramp-up Rate C/second max. C C - seconds C/second max. C C - seconds C/second max. Time maintained above: Temperature (T ) -Time (T ) C - seconds C - seconds Peak Temperature (T P ) +/- C +/- C +/- C +/- C Time within C of actual Peak Temperature (T P ) - seconds - seconds - seconds - seconds Ramp-down Rate Time C to Peak C/second max. C/second max. Temperature minutes max. minutes max. Note: All temperatures refer to topside of the package, measured on the package body surface Note: All temperatures refer to IPC/JDC J-STD-B IT-I9 Rev A Page of

13 Ordering Information The DA IC is available in standard or Pb-free Green MSOP- package per tape and reel. A DA IC Designer s Kit (DDDAA-K) provides a vehicle for evaluating and identifying the optimum component values for any particular application using DA IC. Rogers engineers also provide full support to customers, including circuit optimization and application retrofits. RCOMMNDD PAD AYOUT MSOP- Min Typical Max mm in mm in mm in A B C D F G H I MSOP- PAD AYOUT Min Typical Max mm in mm in mm in a b c.... d e.... f MSOPs in Tape & Reel: DDDAA-M DDDAA-N DDDAA-MO DDDAA-N A xxxx A xxxx mbossed tape on mm diameter reel per IA--. Standard MSOP- Pb-free Green MSOP- units per reel. Quantity marked on reel label. ISO9:, ISO/TS 99:, and ISO:99 Certified The information contained in this data sheet is intended to assist you in designing with Rogers systems. It is not intended to and does not create any warranties, express or implied, including any warranty of merchantability or fitness for a particular purpose or that the results shown on the data sheet will be achieved by a user for a particular purpose. The user should determine the suitability of Rogers systems for each application. These drivers are covered by one or more of the following U.S. patents: #,,;,,9; #,,; #,,99; #,9,; #,,;#,,9 Corresponding foreign patents are issued and pending The world runs better with Rogers. DUR and DFX are licensed trademarks of Rogers Corporation., Rogers Corporation, Printed in U.S.A. All Rights Reserved. Revised / Publication # IT-I9A