Browse Prior Art Database

Integrated MOSFET Full Wave Rectifier and Regulator Circuit

IP.com Disclosure Number: IPCOM000052006D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Zbrozek, JD: AUTHOR

Abstract

The drawing shows an on-chip FET circuit which performs full-wave rectification and voltage regulation. The circuit has a bridge of four FETs with two of the FETs controlled by a circuit responsive to the output voltage.

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Integrated MOSFET Full Wave Rectifier and Regulator Circuit

The drawing shows an on-chip FET circuit which performs full-wave rectification and voltage regulation. The circuit has a bridge of four FETs with two of the FETs controlled by a circuit responsive to the output voltage.

Devices T1, T2, T3 and T4 form a full-wave rectifier bridge, each being an enhancement-mode FET with a threshold voltage of +1. When the transformer secondary winding has a potential from a to b more than +1 volt, T2 clamps b to ground, allowing a to rise positively. Similarly, device T1 clamps terminal a to ground when the sinusoidal input signal is reversed.

If the gates of T3 and T4 were connected to terminals a and b, respectively, the four devices would function as a four-diode bridge. In this circuit a control sub-circuit, as shown, is provided to control the gate signals to device T4 and an essentially identical control sub-circuit (not shown) controls the gate signals to device T3.

In the control sub-circuit, T5 is an depletion-mode FET having a threshold of - 2 volts. It is connected as a differential pair with T6, an enhancement-mode FET having a threshold of +1 volt. FETs 7 and 8 are depletion-mode FETs connected to function as resistors. The gate of T6 is connected to the rectifier output. During one half cycle, assuming the output voltage is less than +3 volts, T5 conducts and the drain of T7 rises to about +2 volts, thereby tending to bias T5 off and establishing circuit equilibrium at which the voltage a...