DC / DC converter for LCDs BP5302A / BP5302XA The BP5302A and BP5302XA are DC / DC converters for supplying power to liquid crystal display (LCD) panels. The modules supply a negative voltage from a positive power supply. They are available in a single in-line package as an upright (BP5302A) or L-shaped lead (BP5302XA) type. Applications LCD panels in personal computers and word processors Features 1) Wide input voltage range.(+5V to +14V) 5) Built-in ON/OFF switch. 2) High accurate output voltage. ( 240.75V) 6) Compact and light. 3) High conversion efficiency. (Typ. 80%) 7) Available as an upright or L-shaped lead type. 4) Built-in protection circuit. Absolute maximum ratings (Ta=25C) Parameter Symbol Limits Unit Input voltage VIN 15 V Operating temperature range Topr 0~60 C Storage temperature range Tstg 30~85 C Electrical characteristics (Unless otherwise noted:Ta=25C, and R1 and R2 resistors in the measurement circuit of Fig.1 are disconnected) Parameter Symbol Min. Typ. Max. Unit Conditions Input voltage VIN 5 14 V Output current IOUT 30 mA Output voltage VOUT 23.25 24.00 -24.75 V VIN=12V, IOUT=20mA Line regulation DV1 0.75 V VIN=5~14V, IOUT=20mA Load regulation DV2 0.5 V VIN=12V, IOUT=0~20mA Ripple nose voltage n1 200 mVP-P VIN=12V, IOUT=20mA Efficiency h70 80 - % VIN=12V, IOUT=20mA ON / OFF CTL votage when ON VCTL 1.5 6.0 V VIN=5~14V 0.5 ON / OFF CTL votage when OFF VCTL VVIN=5~14V (Alternatively, when OPEN) ON / OFF CTL current ICTL 150 A VIN=5~14V, VCTL=5V Current consumption when OFF IOFF 10 A VIN=5~14V, VCTL=0V R1 resistance R1 50 k VIN=5~14V, VCTL=5V R2 resistance R2 20 k VIN=5~14V, VCTL=5V Measured with a band width of 20MHz. 1/4 BP5302A / BP5302XA Pin descriptions Pin No. Pin name Function Output smoothing capacitor connection pin connect a low- 1CO impedance capacitor with a recommended capacitance of 47 F between this pin and GND 2VOUT Output pin Output voltage adjustment pin for contrast output voltage is 3 Vref adjusted by connecting a resistor between pins 2 and 3 or pins 3 and 4 4, 7 GND Ground pin Output ON / OFF control pin output starts when the pin is 8 VCTL HIGH level, and stops when the pin is LOW or OPEN Input pin connect a low-impedance capacitor with a 9VIN recommended capacitance of 100 F between this pin and GND Measurement circuit and Application example BP5302A / BP5302XA 1 2 3 4 7 8 9 Be sure to use fuse for safety VIN (R1) (R2) ON / OFF VOUT SW + C2 C1 + VCTL GND GND Fig.1 C1 : 100 F / 16V (Low impedance) C2 : 47 F / 35V (Low impedance) R1, R2 : Resistors for adjusting output voltage (Disconnected during test measurement) Operation notes (1) Place I/O external capacitors as near as possible to the connection pins. In particular, make sure to minimize the impedance between the input-side capacitor (C1) and pin 9. (Reference value: A length less than 50mm is recommended for a copper foil of 1.0mm wide and 35 F thick.) (2) Avoid frequent switching using the ON/OFF CTL pin (5 times per second at the maximum). (3) R1 and R2 resistors, which are used for changing the output voltage, are usually not required. 2/4