PWM Generator Circuit

PWM generator

Here is an assembly very simple to get an oscillator giving
a fixed frequency signal but variable duty cycle. It can - after
amplifier transistor - serve to control the rotation speed of a motor
with direct current or to adjust the power of a dew-heater. We use
once again a logic gate of a CD4093 circuit.

http://www.astrosurf.com/spectrohelio/schemelek-en.php

A Simple PWM Circuit Based on the 555 Timer

The 555 timer in the PWM circuit is configured as an astable
oscillator. This means that once power is applied, the 555 will
oscillate without any external trigger. Before the technical
explanation of the circuit, let's look at the 555 timer IC itself.

http://www.dprg.org/tutorials/2005-11a/index.html

Opamp PWM Generator Circuit

This uses the LM324, a 14-pin DIL IC containing four individual
op-amps and running off a single-rail power supply.
The sawtooth is generated with two of them (U1A and U1B),
configured as a Schmitt Trigger and Miller Integrator, and
a third (U1C) is used as a comparator to compare the sawtooth
with the reference voltage and switch the power transistor.

http://www.cpemma.co.uk/pwm.html

PWM Generator Circuit by Digital register method

an example circuit using the digital comparison method
when a microcontroller is available to set the 4-bit digital register
value. A write strobe is required from the micro to latch the 4 data
bits into the register. The 74HC161 counter is free-running,
the frequency being set by the 74HC14 oscillator section, where
it is roughly f = 1/(6.3RC). The resulting frequency of the PWM
signal will be 16 times less than this counter clock frequency,
since it requires 16 pulses to complete one "revolution" of the
counter. With R=2k and C=1nF this results in a counter
frequency of approximately 80kHz which will result in a PWM signal
frequency of 5kHz.

homepages.which.net/~paul.hills/Circuits/PwmGenerators

PWM using 555

IC1 astable gives a fixed square wave at pin 3, C1 and R1 derive
uS trigger pulses from IC1 and this will trigger IC2 monostable or
single shot, the voltage at pin 5 of IC2 will change the pulse width
output of IC2, to get it working all the three RC combinations
have to be figured out

schematics.blogspot.com/2004/10/pulse-width-modulation

HALF-BRIDGE MOSFET DRIVER CIRCUIT

IN = PWM 0 to 95%
IR2111
The IR2111(S) is a high voltage, high speed power
MOSFET and IGBT driver with dependent high and
low side referenced output channels designed for halfbridge
applications. Proprietary HVIC and latch
immune CMOS technologies enable ruggedized
monolithic construction. Logic input is compatible with
standard CMOS outputs. The output drivers feature a
high pulse current buffer stage designed for minimum
driver cross-conduction. Internal deadtime is provided
to avoid shoot-through in the output half-bridge. The
floating channel can be used to drive an N-channel
power MOSFET or IGBT in the high side configuration
which operates up to 600 volts.

Features
- Floating channel designed for bootstrap operation
Fully operational to +600V
Tolerant to negative transient voltage
dV/dt immune
- Gate drive supply range from 10 to 20V
- Undervoltage lockout for both channels
- CMOS Schmitt-triggered inputs with pull-down
- Matched propagation delay for both channels
- Internally set deadtime
- High side output in phase with

IR2111 Datasheet pdf

High and Low Side Mosfet Driver Circuit

IR2110
The IR2110/IR2113 are high voltage, high speed power MOSFET and
IGBT drivers with independent high and low side referenced output channels.
Proprietary HVIC and latch immune CMOS technologies enable
ruggedized monolithic construction. Logic inputs are compatible with
standard CMOS or LSTTL output, down to 3.3V logic. The output
drivers feature a high pulse current buffer stage designed for minimum
driver cross-conduction. Propagation delays are matched to simplify use in
high frequency applications. The floating channel can be used to drive an
N-channel power MOSFET or IGBT in the high side configuration
whichoperates up to 500 or 600 volts

Features
- Floating channel designed for bootstrap operation
Fully operational to +500V or +600V
Tolerant to negative transient voltage
dV/dt immune
- Gate drive supply range from 10 to 20V
- Undervoltage lockout for both channels
- 3.3V logic compatible
Separate logic supply range from 3.3V to 20V
Logic and power ground 5V offset
- CMOS Schmitt-triggered inputs with pull-down
- Cycle by cycle edge-triggered shutdown logic
- Matched propagation delay for

IR2110 Datasheet pdf