Panasonic AN8038 free download

File name AN8038.pdf

Voltage Regulators AN8038, AN8038S AC-DC switching power supply control IC with RCC local resonance circuit for improved conformance with energy conservation laws s Overview The AN8038 and AN8038S are self-excited AC-DC switching power supply control IC that adopt RCC local resonance control. These ICs are designed to achieve high efficiency over a wide range of loads (light loads at the standby mode to heavy loads) for improved conformance with energy conservation laws, and support input levels used worldwide. They are particularly appropriate for use in AV and OA equipments. AN8038 Unit: mm 0.5±0.1 0.51 min. 3.8±0.25 (3.45) 1 8 7 9.4±0.3 2 3 4 6.3±0.3 5 3° to 15° 7.62±0.25 0.15­0.05 +0.1 DIP008-P-0300B s Features AN8038S 5.01±0.20 · Supports improved conformance with energy conser8 5 vation laws by providing two operating modes. With external resistors, it is possible to set the operating point at which the modes change over according to the load power, as shown below. 1.Continuous (RCC) mode 1 4 High efficiency achieved with local resonance operation (zero cross detection). 2.Discontinuous mode (standby) mode Reduced switching loss and standby power due to re(0.60) 1.27 0.40 duced frequency 0.10 Seating plane · Input voltage correction function. This function corrects SOP008-P-0225C the maximum on-period in a manner inversely proportional to the input voltage. · Built-in overvoltage protection function (detects at VCC pin) · Pulse-by-pulse overcurrent protection function (single detection per one cycle) · Packages: 8-pin DIP ··· AN8038 8-pin SOP ··· AN8038S 4.30±0.20 6.40±0.20 0.15±0.10 +0.10 ­0.05 Unit: mm (1.05) 0° to10° 0.50±0.20 s Applications · Facsimiles and other OA equipment · Printers and other personal computer peripheral equipment · AV equipment 1.45±0.10 1.75 max. 2.54 6 1.2±0.25 1 AN8038, AN8038S s Block Diagram Voltage Regulators OVP OVP R S (SD latch) Q INIT 8 VCC Start Stop VREF 7V 7V Current reviser (IFB) 2 17.5 k 17.5 k Q Q Q VFB TON 4.2 V High-side clamp TR 1 Low-side clamp Current reviser (ITR) RQ S (TR latch) 0.25 V CF 3 Q Q In In 7 6 Out GND RSTB Out drive CF latch IFB 4 I/V conv. Q S R R - 0.2 V 5 CLM TOFF 1.0 V 2 Voltage Regulators s Pin Descriptions Pin No. Symbol 1 TR Description AN8038, AN8038S Transformer reset. When a transformer reset is detected, i.e., a low level is input to this pin, the IC output goes high. However, the transformer reset signal is ignored during the minimum off-period determined by the CF pin. The maximum on-period is also corrected according to the current flowing out of this pin. Adjusts the light-load detection level that determines the when the IC switches from RCC to discontinuous operation. When the voltage (VFB) which is I-V conversion of current feedback signal from IFB pin goes up higher than this pin, minimum off-period current at CF pin decreases, and operating frequency decreases. The detection level can be adjusted arbitrarily using an