Switch Mode Power Supply
Created: May 19, 2016
No description available.
The power supply is one of the most common and important parts of a circuit design that converts one form of electrical energy to another. The traditional designs of power supply use analog ICs with fixed functionality to provide regulated power. With the recent interest in intelligent power supplies has driven the development of a new class of microcontroller friendly PWM generators. The PIC10F206 is a low-cost high-performance 8-bit microcontroller that has an on-chip voltage comparator for the under-voltage detect and it has sufficient I/O to control the PWM modulator, since the PWM modulator does not contain an on-chip oscillator, and monitor the external inputs.
The power supply design combines the PIC10F206 microcontroller and the MCP1630 PWM modulator. The design is a full proportional-feedback continuous inductor current, current-mode, boost power supply that can generate 15V with 250mA output from a 9V dc input. The microcontroller monitors the inputs and generates the 250kHz clock for the PWM modulator. The inputs of the microcontroller are connected to a voltage divider [R2 & R3], a digital temperature sensor [U4] and the shutdown input [GP1 pin]. For under-voltage detection, the connection at pin GP0 is routed to the non-inverting input of the comparator. The inverting input is tied internally to the on-chip 0.6V reference. The software of the microcontroller monitors the input to detect an over temperature condition and shutdown the pulse output if the temperature goes too high. When the temperature falls back below the threshold temperature, the sensor output returns high and the software soft-starts the pulse output.
The PIC10F206 microcontroller is suited in applications like security system, personal care appliances, and low power remote transmitters and receivers. With the combination of software and simple hardware, an efficient control for a PWM generator is implemented with many of the features found in more complex controllers. The result is a modular building-block style design with many advanced features that can be easily customized for a customer’s needs.