Method for operating an H-bridge drive utilizing a pair of high and low side MOSFETS

• US 7,465,610 B2
• Filed: 08/14/2006
• Issued: 12/16/2008
• Est. Priority Date: 03/04/2002
• Status: Expired due to Term

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: de Frutos, Xavier, Thiery, Vincent, Nadd, Bruno C., Lee, Chik Yam
• Primary Examiner(s): Chambliss; Alonzo
• Application Number:
  US11/503,792
• Publication Number:
  US 20060275970A1
• Time in Patent Office: 855 Days
• Field of Search: None
• US Class Current: 438/142
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H02H 7/0838 with H-bridge circuit
• CPC Class Codes: H02P 2203/07 Motor variable determination based on the ON-resistance of a power switch, i.e. the voltage across the switch is measured during the ON state of the switch and used to determine the current in the motor and to calculate the speed
• CPC Class Codes: H02P 7/04 by means of a H-bridge circuit

Abstract

A fully protected H-bridge for a d-c motor consists of two high side MOSFETs and a control and logic IC on a first conductive heat sink all within a first package and two discrete low side MOSFETs. The entire bridge is controlled by the IC. Shoot thru protection is provided for each leg, and a PMW soft start sequence is provided through the control of the low side MOSFETs, programed by an external, chargeable RC circuit. Input signals to the high side MOSFETs select the operation modes. Protective circuits are provided for short circuit current and over current conditions. Sleep mode and braking/non braking control is also provided.

Claims

1. A method for preventing a shoot through event in a bridge circuit comprising a high side switch and a low side switch connected at an output node, comprising:

measuring a voltage across said low side switch;

providing a reference voltage;

comparing said reference voltage to said voltage across said low side switch; and

turning on said low side switch when said voltage across said low side switch has reached said reference voltage wherein the comparing is carried out by a comparator.

2. A method according to claim 1, wherein said high side and said low side switches are MOSFETs.

3. A method according to claim 2, wherein said voltage is the drain to source voltage across said low side MOSFET.

4. A method according to claim 1, wherein said voltage across said low side switch is measured between said output node and ground.

5. A method according to claim 1, wherein said comparing is carried out by a comparator.

6. A method according to claim 5, wherein said comparator receives said voltage across said low side switch and said reference voltage.

7. A method according to claim 6, wherein said reference voltage is 2 volts.