A design of high voltage pre-regulator circuit for LED driver

An internal pre-regulator circuit used in high voltage LED driver circuit is presented to provide stable power supply voltage input for the low voltage module in the system. The circuit is mainly composed of three parts: high voltage pre-regulator circuit, low voltage reference voltage source and linear regulator. Unlike the traditional linear regulator, which uses voltage regulator diode reverse breakdown characteristic to stabilize the voltage, this design uses a low voltage reference voltage source to generate accurate reference voltage, which is fed back to the high voltage pre-regulator circuit to achieve negative feedback regulation of the output voltage of the pre-regulator circuit. The precision of output voltage is improved effectively, the area of chip is reduced, and the dependence of design on process is reduced. Through the simulation of Huahong NEC 0.35m 40V BCD process model, the output voltage of the pre-stabilized circuit is stable.