AiT Semiconductor has introduced A8180A, a continuous mode inductive step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. This LED driver operates from an input supply between 6 V and 36 V and provides an externally adjustable output current of up to 1 A. Depending upon supply voltage and external components, this can provide up to 30 Watts of output power. The A8180A includes the output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current.

Output current can be adjusted below the set value, by applying an external control signal to the VSET pin. The VSET pin will accept either a DC voltage or a PWM waveform. The soft-start time can be increased using an external capacitor from the VSET pin to ground. Applying a voltage of 0.2 V or lower to the VSET pin turns the output off and switches the device into a low current standby state.

Key features of A8180A

1. Simple low parts count
2. Internal 40 V NDMOS switch
3. 1 A output current
4. Single pin on/off and brightness control Using DC voltage or PWM
5. Soft-start function
6. High efficiency (up to 97%)
7. Wide input voltage range: 6 V to 36 V
8. Open LED Protection
9. Short LED Protection
10. Up to 1 MHz switching frequency
11. Typical 5% output current accuracy
12. Available in SOT89-5 package

Applications

1. Low voltage halogen replacement LEDs
2. Low voltage industrial lighting
3. LED back-side lighting