Circuit for providing fast output current control in a current mode switching power supply

• US 5,003,456 A
• Filed: 01/06/1989
• Issued: 03/26/1991
• Est. Priority Date: 01/06/1989
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Uniphase Corporation
• Inventors: Forge, Charles O.
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US07/294,635
• Time in Patent Office: 809 Days
• Field of Search: 363/39, 363/44, 363/45, 363/46-48, 363/78-80, 363/89, 363/124, 323/282, 323/285, 372/38
• US Class Current: 363/89
• CPC Class Codes: G05F 1/563 including two stages of regulation at least one of which is output level responsive, e.g. coarse and fine regulation
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A circuit for providing current to a laser tube permits high current, high output voltage, and high frequency modulation response (e.g., up to about 1 MHz, in one embodiment) with low power dissipation. This is accomplished by combining the output current from two current sources, one of which is a high amplitude low frequency current mode switched mode power supply, while the other current source is a low amplitude, high frequency current source.

Claims

1. A power supply comprising:

means for receiving a first control signal;

first means for generating a first current in response to low frequency components of said first control signal;

second means for generating a second current in response to high frequency components of said first control signal; and

output means for generating an output current in response to said first and second currents wherein said output current is a substantially flat frequency function of said first control signal.

2. Power supply of claim 1 wherein said output means comprises a resistor and capacitor coupled in parallel with said first means, said parallel-coupled resistor and capacitor coupled in series with an equivalent of an inductor coupled in parallel with said second means.

3. Power supply of claim 2 wherein said equivalent comprises a transformer having a first winding coupled across said second means and a second winding coupled in series with said parallel-coupled resistor and capacitor.

4. Power supply of claim 3 wherein said output means is coupled across a laser tube.

5. Power supply of claim 1 wherein said first means is current mode switching power supply.

6. Power supply of claim 5 wherein said second means is responsive to frequency components of said first control signal greater than a switching frequency of said current mode switching power supply.

7. Power supply of claim 6 wherein said second means is responsive to components of said first control signal having frequencies on the order of 1 MHz.

8. Power supply of claim 6 wherein said second means comprises a transistor amplifier.

9. Power supply of claim 1 wherein said first means and said second means each comprise a resistor coupled in series with a voltage source.

10. Power supply of claim 1 wherein said second means is responsive to frequency components having at least twice the frequency of the highest frequency components that said first means is responsive to.

11. A power supply comprising:

means for receiving a first control signal;

first means for generating a first current in response to low frequency components of said first control signal;

second means for generating a second current in response to high frequency components of said first control signal; and

output means for generating an output current in response to said first and second currents wherein said output current is a particular function of said first control signal.