The AD8240 LED driver/monitor, in combination with an external transistor, supplies a constant 12 V to drive LED lamps. This allows cost-effective LED lamp monitoring and short-circuit protection. The output is regulated at 12 V when the supply voltage is between 12.5 V and 27 V. A CMOS compatible, level-dependent, digital input can be used for PWM control of the LED brightness. VO is turned on when the PWM input is high and turned off when the input is low. The product also provides LED on/off detection and latch-off overcurrent protection.
The AD8240 is an LED driver and monitor that supplies a constant 12 V to drive LED lamps while offering PWM‑controlled brightness, open‑LED detection, and latch‑off over‑current protection. It operates from a 9 V to 27 V supply and uses an external transistor for low‑power operation.
The device includes a high‑side current‑sense amplifier (gain 24) for monitoring LED current, a comparator that latches off the output when the sense voltage exceeds 5 V, and a linear regulator block that provides a stable output voltage. Typical automotive applications include brake, turn‑signal and running lamps where partial‑LED failure monitoring is required.
| Supply Voltage Range | 9 V to 27 V |
|---|---|
| Regulated Voltage Range | 12.5 V to 27 V |
| Operating Current | 300 pA |
| Shutdown Current | 10 pA |
| PWM Frequency Range | up to 500 Hz |
| Package | 8‑lead MSOP |
| Vsense Gain | 24 |
The PWM input controls LED brightness and can also serve as a simple on/off control.
A comparator monitors the high‑side current‑sense amplifier; when its output exceeds 5 V the comparator trips and latches off the driver output.
The output is regulated at 12 V when the supply voltage is between 12.5 V and 27 V.