Maxim's MAX1531 multiple-output, power-supply controllers generate all the supply rails for thin-film transistor (TFT) liquid-crystal display (LCD) monitors. The MAX1531 includes a high-efficiency, fixed-frequency, step-down regulator. The low-cost, all N-channel, synchronous topology enables operation with efficiency as high as 93%. High-frequency operation allows the use of small inductors and capacitors, resulting in a compact solution. The MAX1531 includes five linear regulator controllers for supplying logic and LCD bias voltages. A programmable startup sequence enables easy control of the regulators.
The MAX1531 includes soft-start functions to limit in-rush current during startup. An internal step-down converter current-limit function and a versatile overcurrent shutdown to protect the power supplies against fault conditions. The MAX1531 uses current-mode control architecture, providing fast load transient response and easy compensation. An internal linear regulator provides MOSFET gate drive and can be used to power small external loads.
The MAX1531 can operate from inputs as high as 28 V and is well suited for LCD monitor and TV applications running directly from AC/DC wall adapters. The MAX1531 is available in a small (5 mm x 5 mm), ultra-thin (0.8 mm), 32-pin QFN package and operate over a -40°C to +85°C temperature range.
- 4.5 V to 28 V input voltage range
- 250 kHz / 500 kHz current-mode step-down converter
- Small inductor / capacitors
- No sense resistor
- Three positive linear regulator controllers
- One positive and one negative additional controller
- Small input and output capacitors
- Timed reset output
- Uncommitted overcurrent protection
- Soft-start for all regulators
- Programmable input undervoltage comparator
- Programmable startup sequencing
- Automotive LCDs
- LCK monitors