555 timer as a switch-mode power supply

Most switch-mode power supplies rely on a PWM (pulse-width-modulated) output that is controlled via voltage feedback. A 555-timer IC can inexpensively perform PWM. The circuit in Figure 1 shows how to turn a 555 PWM circuit into an switch-mode power supply with only one simple equation. The design uses two 555s. IC1, in astable mode, triggers IC2 in PWM mode. IC1 is set to oscillate at approximately 60 kHz at a high duty cycle.

Read More Source:http://www.edn.com/article/CA257052.html
Thank you.

Autoformer Switch-Mode Power Supply
This is a small 2*25 (actually, 2*50) WPC amplifier with 3-order crossover stage (configurable as LP or HP). Of particular interest is the unconventional autoformer PS arrangement. Since the p ...
L296 Switching power supply Regulator 0-40V 4A
Specificaly for the chip that is used in this circuit data are like this: Oscilator runs at freq 200kHz, output noise is below 1% (worst case), max current is 4A at 20V. Voltage can be regulat ...
Step down voltage converter 5v with transistor BC337
The circuit decreases the size voltage or Stepdown Voltage converter circuit be dc regulated circuit model switching converter. The that make voltage output there is the size voltage a little more ...
simple switching power supply by LM393
I built a PCB for a simple switching power supply, originally designed by Keith Payea of the SRS. It uses an LM393, a P-channel power MOSFET, and darn little else. Since its frequency varies based ...
DC to DC step down voltage regulator by IC LM2575 (1A)
DC to DC step down voltage regulator. Wide input voltage 8Vdc to 40Vdc. Part number: - LM2575-3.3 (3.3Vdc output) - LM2575-5.0 (5Vdc output) - LM2575-12 (12Vdc output) - L ...