PWM using LM339 Circuit Diagram

This is simple IC based PWM using LM339 Circuit Diagram. PWM or Pulse Width Modulators using LM339 is an Electronic circuit.The first example uses the standard op-amp oscillator circuit to generate a triangular waveform which is level-shifted and fed to a comparator (e.g. LM339) to give the PWM waveform. Most people will want to use two comparators rather than one op-amp and one comparator.

 PWM using LM339 Circuit Diagram

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Simple 5V Supply High-Side Switcher Circuit Diagram

This is a Simple 5V Supply High-Side Switcher Circuit Diagram. This circuit requiring only 10uA of quiescent current, the circuit of (Fig. 62-1 (a)) produces only 0.1ohm ON-rises-trance. IC1 is a charge pump voltage converter to produce a 5V level, so analog switch IC2 can provide a 10-V swing to MOSFET Ql. 

5V Supply High-Side Switcher Circuit Diagram

This circuit uses a voltage converter to enable the analog switch to apply a 4.3V swing to logic level NMOS power transistor Q1. ON resistance is 0.03ohm typical. This circuit uses additional stages in the voltage-multiplying circuit to provide a higher gate voltage swing. This would enable the use of a converter for an NMOS switching transistor.

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Mosfet Mixer Oscillator For Am Receivers Circuit Diagram

This is a simple Mosfet Mixer Oscillator For Am Receivers Circuit Diagram. This circuit is an improved front end for upgrading a transistor AM receiver. This front end is useful when the radio is to be used as a tune-able IF amplifier with shortwave converters. 

Mosfet Mixer Oscillator For Am Receivers Circuit Diagram

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Simple Mosfet Buffer Amplifier Circuit Diagram

This is a Simple Mosfet Buffer Amplifier Circuit Diagram, A MOSFET is used as a wide-band buffer amplifier. T1 is wound on a toroid of approximately /f diameter, with material suitable for frequency (usually 1- to 20-MHz range). The turns ratio should be about 4:1 depending on load impedance. Typically, at 4 MHz, there are 18 turns on the primary, 4 turns on the secondary, and the stage gain is about 14-dB voltage (ZL - 50 ). 

Simple Mosfet Buffer Amplifier Circuit Diagram

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A Charge Pump Circuit Diagram

A charge pump is a kind of DC to DC converter that uses capacitors as energy storage elements to create either a higher or lower voltage power source.This is a Positive input and negative output charge pump. The 74Cl4 IC is a self-oscillating driver for the MOSFET power switch. 

 A Charge Pump Circuit Diagram

It produces a pulse width of 6.5 p,s at a repetition frequency of 100 kHz. When the MOSFET device is off, capacitor C is charged to the positive supply. When the power through the MOSFET switches on, C delivers a negative voltage through the series diode to the output. The zener serves as a dissipative regulator. Because the MOSFET switches fast, operation at high frequencies allows the capacitors in the system to be small.

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Scarce Level Power Fet Driver Method Circuit Diagram

This is the Scarce Level Power Fet Driver Method Circuit Diagram. This circuit operates from a 16- to 50-V supply. Adding the buffer circuit (within the dashed lines) offers 100-ns switching times. Otherwise, the circuit switches in 1 /xs. Ql and R1 form a switched current source of about 12 mA. 

The current flows through R2, which supplies 12 V to the FET. The circuit works well over a wide range of supply voltages. Furthermore, it switches smoothly in the presence of large ripple and noise on the supply. 

 Scarce Level Power Fet Driver Method Circuit Diagram

The switching time (about 1 /as) can be reduced considerably by lowering the values of Ri and R2 at the expense of higher power dissipation in the resistors and Ql. Alternatively, a buffer circuit can be added to produce switching times of 100 ns without generating significant power dissipation.

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