LED power supply without transformer circuit diagram

ZD832 driving a string of LEDs in series at a presetted constant current

Circuit diagram with ZD832 high voltage, TransformerFree™ AC-DC constant current power supply without transformer driver for driving a string of white or RGB LEDs in series. It operates from an universal input voltage of 85VAC to 125VAC, or 180VAC to 240VAC and generates a programmable constant output current.

The high operating voltage of ZD832, along with its linear control architecture eliminates the need for an external inductor, transformer and rectifying diode bridge. The output current level is set by a single resistor and can be set as high as 30mA. Dimming control can be accomplished by using pulse-width modulation signal with varying duty cycle on the PWM pin or by applying an analog DC voltage on the ISET pin.

Thermal and overvoltage circuitry protects the internal power transistors from excessive power dissipation.

Download Source: Universal TransformerFree™ AC-DC Constant Current LED Driver Zywyn Corporation