Simple DC to DC Converter Circuit

This is a circuit for converter voltage. This circuit is DC to DC converter using a standard 12 VAC center tapped power transformer wired as a blocking oscillator. The circuit is not very efficient but will produce a high voltage usable for low power applications. This is the figure of the circuit.


The input battery voltage is raised by a factor of 10 across the transformer and further raised by a voltage triple consisting of three capacitors and diodes connected to the high voltage side of the transformer. The circuit draws about 40 milliamps and should operate for about 200 hours on a couple of 'D' alkaline batteries. Higher voltages can be obtained by reducing the 4.7K bias resistor.

Simple 20 Watt Switcher Forward Converter

This is design circuit for step-down regulator can be developed using the LM2577 Simple Switcher IC in a forward converter topology. This design allows the LM2577 IC to be used in step-down voltage applications at output power levels greater than the 1 A LM2575 and 3 A LM2576 buck regulators. This is the figure of the circuit.

Diodes, DR and DF, used in the secondary are 5A, 30V Schottky diodes. The same diode type is used for Dc, however a lower current diode could have been used. A compensation network of Rc and Cc optimizes the regulator’s stability and transient response and provides a soft-start function for a well-controlled power-up. [Circuit source: National Semiconductor Notes].

Simple Step-up PWM DC-DC Converter Integrated with 4 Buffers

This is a circuit for converter that is a simple form for DC to DC Converter circuit. This circuit is based on LM2711 from National Semiconductor. This is the figure of the circuit;

The LM2711 has a current mode PWM step-up DC/DC converter with a 1.4A, 0.17 internal switch. Capable of generating 8V at 300mA from a Lithium Ion battery, the LM2711 is ideal for generating bias voltages for large screen LCD panels. The LM2711 can be operated at switching frequencies of 600 KHz or 1.25MHz, allowing for easy filtering and low noise. An external compensation pin gives the user flexibility in setting frequency compensation, which makes possible the use of small, low ESR ceramic capacitors at the output. The LM2711 uses a patented internal circuitry to limit startup inrush current of the boost switching regulator without the use of an external soft start capacitor. An external soft start pin enables the user to tailor the soft start to a specific application. The LM2711 contains 4 Gamma buffers capable of supplying 50mA source and sink. The TSSOP-20 package ensures a low profile overall solution. [Schematic circuit source: National Semiconductor Notes]