US 8,284,581 B2Granted

Active rectifier and method for energy harvesting power management circuit

AssigneeTexas Instruments Incorporated

InventorVadim V. Ivanov

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Abstract

An active rectifier (12) couples a first input voltage (Vin1) to a first electrode of a first transistor (M3) having a second electrode coupled to an output (4) conducting an output voltage (Vout), and couples a second input voltage (Vin2) to a first electrode of a second transistor (M4) having a second electrode coupled to the output conductor. A first amplifier (A1) controls a voltage (V16) of a gate of the first transistor to maintain an input offset of the first amplifier between the first input voltage and the output voltage while the first input voltage exceeds the output voltage, and a second amplifier (A2) controls a voltage (V15) on a gate of the second transistor to maintain an input offset between the second input voltage and the output voltage while the first input voltage exceeds the output voltage. The input offsets prevent backflow of current from the output to either of the first electrodes when the first or second input is nearly equal to the output voltage.

Claims20

Dependent claims

An active rectifier circuit comprising:

(a) a first transistor having a first current-carrying electrode coupled by a first input conductor to a first input voltage and a second current-carrying electrode coupled to an output conductor for conducting a rectified output voltage, and a second transistor having a first current-carrying electrode coupled by a second input conductor to a second input voltage and a second current-carrying electrode coupled to the output conductor;
(b) a first amplifier having a first input coupled to the first input conductor, a second input coupled to the output conductor, and an output coupled to a gate of the first transistor, and a second amplifier having a first input coupled to the second input conductor, a second input coupled to the output conductor, and an output coupled to a gate of the second transistor;
(c) a third transistor having a first current-carrying electrode coupled to a first reference voltage, a second current-carrying electrode coupled to the first input conductor, and a gate coupled to the output of the second amplifier, and a fourth transistor having a first current-carrying electrode coupled to the first reference voltage, a second current-carrying electrode coupled to the second input conductor, and a gate coupled to the output of the first amplifier;
and
(d) the first and second amplifiers each having an input offset voltage to limit or prevent backflow of current from the output conductor to either of the first and second input conductors when either of the first and second input voltages, respectively, is nearly equal to the output voltage.

2 more elements

A method for rectifying a low voltage AC input signal that is equal to a first input voltage minus a second input voltage to produce a rectified output voltage, the method comprising:

(a) coupling the first input voltage to a first current-carrying electrode of a first transistor having a second current-carrying electrode coupled to an output conductor for conducting the rectified output voltage, and coupling the second input voltage to a first current-carrying electrode of a second transistor having a second current-carrying electrode coupled to the output conductor;
(b) controlling a first voltage on a gate of the first transistor by means of a first amplifier to maintain a predetermined offset voltage of the first amplifier between the first input voltage and the rectified output voltage while the first input voltage exceeds the rectified output voltage, and controlling a second voltage on a gate of the second transistor by means of a second amplifier to maintain a predetermined offset voltage of the second amplifier between the second input voltage and the rectified output voltage while the first input voltage exceeds the rectified output voltage;
(c) the predetermined offset voltages limiting or preventing backflow of current from either of the second current-carrying electrodes to a corresponding first current-carrying electrode when either of the first and second input voltages, respectively, is nearly equal to the rectified output voltage.

Dependencies are inferred from the claim text.

Facts

Application: 12/653,005Filed 7 Dec 2009
Published: US 2011/0134674 A19 Jun 2011
Granted: 9 Oct 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H02M 7/219
Using semiconductor devices only: in a bridge configuration
H02M 7/2195
In a bridge configuration: the switches being synchronously commutated at the same frequency of the AC input voltage
H03K 2017/307
Modifications for providing a predetermined threshold before switching: circuits simulating a diode, e.g. threshold zero
Y02B 70/10
Technologies for an efficient end-user side electric power management and consumption: technologies improving the efficiency by using…