High voltage level shifter via capacitors

• US 20030107425A1
• Filed: 12/11/2001
• Published: 06/12/2003
• Est. Priority Date: 12/11/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Yushan, Li
• Granted Patent: US 6,646,469 B2
• Time in Patent Office: Days
• US Class Current: 327/333
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption

Abstract

A driver circuit is disclosed for driving a half bridge driver or similar circuit. The driving circuit induced transient currents in two passive devices, and utilizes the transient currents to set or reset a latch at appropriate times required to properly drive a half bridge driver or similar type of circuit.

Claims

1. A level shifting circuit comprising:

plural passive devices, each device being arranged to induce a transient current at specified predetermined times; and

a latch that is connected to said passive devices in a manner such that the induced currents set and reset said latch at appropriate predetermined times.

2. The level shifting circuit of claim 1 wherein said plural passive devices comprise at least two capacitors, each capacitor having terminals.

3. The level shifting circuit of claim 2 wherein a terminal of a first of said capacitors is connected to a first driver, and a terminal of a second of said capacitors is connected to a second driver, and wherein said first driver outputs a signal that is inverted with respect to said output of said second driver.

4. The circuit of claim 3 further comprising a nonoverlapping generator for generating at least two nonoverlapping periodic waveforms, at least one of which is input to an input of said first driver.

5. The circuit of claim 4 wherein a second of said nonoverlapping waveforms is connected to an amplifying transistor through a driver.

6. The circuit of claim 5 wherein a second terminal of each of said capacitors is connected to both a resistor and an input transistor.

7. The circuit of claim 6 wherein each input transistor has a drain, and wherein said drains are connected to different inputs of said latch, one of said drains being connected to a set input of said latch, and another of said drains being connected to a reset input of said latch.

8. The circuit of claim 7 wherein said latch has an output, and said output is connected to a driver.

9. A method of driving a half bridge driver comprising the steps of:

inducing two transient currents in two passive devices, each of said currents being induced at a different time, and

utilizing said induced transient currents to set and reset a latch at prescribed times.

10. The method of claim 9 wherein said transient currents are induced by rapidly changing a voltage across a capacitor.

11. The method of claim 10 wherein the output of the latch is input to a driver.

12. The method of claim 10 wherein the transient currents are induced via a periodic signal that is input to a first driver, and wherein an output of said first driver is input to a second driver.

13. The method of claim 12 wherein said first driver and said second driver produce signals that are compliments of each other.

14. The method of claim 13 further comprising the step of producing nonoverlapping waveforms, one of which is utilized as input to said first driver, and another of which is utilized to drive a transistor.