2

USING THE EVALUATION BOARD

1) Vin requirements and PWM pin

The user of the SP7616 will need to supply Vin and an PWM signal that is active high. The

PWM pin signal is a logic level signal and should range between 0 an 5V. The threshold is 2.4V

for a logic high.

2) Setting the LED current

The LED current is set through the Iset resistor. The SP7616 provides an internal reference

(1)

Where

In example 1: For a 20mA LED current, the current set resistor should be

R2=1V*920/20mA (kΩ),

R2=46K

3) LED dimming

PWM dimming

The LED dimming control is done through the PWM pin. The acceptable frequency range of this

signal is 100Hz to 5 kHz. The acceptable duty cycle range of the signal is 10% to 90% at 1KHZ.

When the PWM pin is driven low, only the LED current sources are disabled while the rest of the

chip is still enabled. .

Analog dimming control

Besides digital PWM control, the LED current can be controlled continuously (from high to low

on the Led current

(2)

Where

1V