STP4CMP

Detailed description

DocID15770 Rev 3

11/24

5

Detailed description

The STP4CMP is a charge-pump-based 4-channel LED driver designed for RGB

illumination or LCD display backlighting, using constant current topology. Each of the 4

channels can be controlled independently. When ONx is pulled high, a constant current is

sunk into the LEDx pin when one LED is connected. This constant current is defined or

5.1

Enable pin

The active high enable input pin is used to shut down the whole device. When this pin is

pulled low, the device goes into shutdown mode with 5 μA max. current consumption only.

An internal pulled down of 300 kΩ is present on this pin.

5.2

LED turn-on pin (ONx)

When the EN pin is pulled high, the STP4CMP provides the flexibility to control ON/OFF on

the 4 channels independently through the 4 active high ON pins. To control the brightness

of each LED channel, it is possible to drive the selected ON pin with a PWM signal with a

frequency up to min. 33 μs T

pins.

5.3

Programmable output current

The LED currents on the 4 channels are programmed individually through a resistor

5.4

Charge pump

The STP4CMP charge pump can be disabled or enabled according to the CP_SEL pin.

When enabled (CP_SEL is high), the charge pump provides a clamping voltage of typ. 5.0

V to ensure enough headroom to drive the LEDs. An internal pull-

down of 300 kΩ is

present on this pin. The charge pump can be disabled by pulling low the CP_SEL pin,

5.5

Thermal protection

The thermal protection circuit ensures the device shutdown when it is overheated (for

example, due to an output short-circuit) to typ. 150 °C. The device resumes normal

operation when the temperature drops by 15 °C from the thermal shutdown threshold.