High efficiency DC step-up voltage converter

• US 5,929,614 A
• Filed: 06/13/1997
• Issued: 07/27/1999
• Est. Priority Date: 06/13/1997
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Copple, Earl James
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US08/874,852
• Time in Patent Office: 774 Days
• Field of Search: 323/282, 323/222, 323/351
• US Class Current: 323/222
• CPC Class Codes: H02M 3/155 using semiconductor devices only

Abstract

A DC power converter is disclosed for converting an input voltage to a final output voltage that is higher than the input voltage. The power converter includes an input terminal for receiving the input voltage and a final output terminal. A boost converter generates an intermediate voltage that is higher than the input voltage and lower than the final output voltage. The boost converter includes an inductor having a primary winding that has a first end connected to the input terminal, a switch for selectively connecting the second end of the first winding to ground, a first diode connected between the second end of the first winding and an intermediate node, and a first output capacitor connected between the intermediate node and ground. The boost converter produces at the first output capacitor an intermediate voltage higher than the input voltage. The step up converter described further includes a second winding on the inductor, a first end of which is connected to receive the intermediate voltage. A diode is connected between the second end of the second winding and the converter output terminal. A second output capacitor is connected between the converter output terminal and ground.

Claims

1. A step-up DC switching voltage converter to produce an output voltage that is higher than an input voltage, the converter comprising:

a) an input terminal for receiving an input voltage;

b) an output terminal;

c) a magnetically coupled inductor having;

i) a first stage winding connected to the input terminal; and

ii) a second stage winding magnetically coupled to the first stage winding;

d) a diode connected in series between the first and second stage windings, the diode connecting the first and second stage windings in a voltage adding fashion;

e) a field regulating switch connected between the first and second stage windings and ground to regulate a magnetic field between the coupled first and second stage windings such that the voltage across the field regulating switch when the switch is in an open position is the sum of the input voltage and the voltage across the first stage winding;

f) a regulator control circuit to trigger the operation of the field regulating switch when the voltage at the output terminal falls below a preset level; and

g) the voltage at the output terminal being the sum of the first stage winding voltage, the second stage winding voltage and the input voltage.

2. The step-up converter of claim 1 further comprising a first filter capacitor connected between the second stage winding and ground, a second filter capacitor connected between the second stage winding and the output terminal, and second diode connected between the second stage winding and the output terminal to further filter the output voltage.

3. A step-up voltage converter of claim 2 wherein the regulator control circuit compares the output voltage to a reference voltage to thereby maintain the output voltage at a preset level by triggering the field regulating switch.

4. A step-up voltage converter of claim 3 wherein the field regulating switch comprises a switching transistor.

5. A step-up voltage converter of claim 4 wherein the switching transistor is a Field Effect Transistor.

6. A step-up voltage converter of claim 2 wherein the first stage winding comprises a number of turns and the second stage winding comprises a number of turns and the number of turns on the first stage winding is equal to the number of turns on the second stage winding such that the first voltage is about equal to the second voltage.

7. A method of increasing a voltage with a step-up DC switching voltage converter comprising the steps of:

a) generating an input voltage at an input terminal;

b) generating a first voltage on a first stage winding of a coupled inductor from the input voltage;

c) generating a second voltage on a second stage winding of the coupled inductor from the first stage winding magnetically coupled thereto;

d) operating a field regulating switch in electrical communication with the inductor to control a first magnetic field of the first stage winding and a second magnetic field coupled to the first magnetic field in response to a preselected output voltage;

e) combining the input voltage, the first voltage and the second voltage through a diode connected in series between the first and second stage windings to produce an output voltage that is the sum of the input voltage, the first stage winding voltage and the second stage winding voltage.

8. The method of claim 7 wherein a regulator control circuit is in communication with the switch and the output terminal to trigger the field regulating switch.

9. The method of claim 8 wherein the field regulating switch is a Field Effect Transistor.

10. The method of claim 9 wherein the first stage winding comprises a number of turns and the second stage winding comprises a number of turns and the number of turns on the first stage winding is equal to the number of turns on the second stage winding such that the first voltage is about equal to the second voltage.