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US 7,254,000 B1Granted
Over voltage protection scheme for synchronous buck converter
AssigneeNexem, Inc.
InventorsMark Smith, Chongming Qiao, Vincent Condido, Reza Amironi, Amir Asvadi
Life of this patent
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Abstract
An over voltage protection circuit for single phase and multiphase buck converters. According to one embodiment, upon the occurrence of an over voltage condition, the high side switch is turned Off and the low side switch is On. As the output voltage drops below a lower threshold, the low side switch is turned Off thereby reducing or eliminating negative spikes on the voltage output.
Claims20
An over voltage protection circuit in a buck converter, comprising:
- at least one switching section in said buck converter, each said section having a high side switch and a low side switch regulating an output voltage of said buck converter, said over voltage protection circuit comprising:
- a voltage sensing network electrically coupled to said output voltage;
- a comparator having a first input electrically coupled to said voltage sensing network, and a second input electrically coupled to a reference voltage and wherein a comparator output is electrically coupled to said low side switch;
- and
- a latch having a latching input electrically coupled to said comparator output and a latching output electrically coupled to said high side switch, wherein said low side switch is coupled to said comparator output without said latch;
- and
- wherein said over voltage protection circuit controls said low side switch and said high side switch to protect a load during an over voltage condition, such that during said over voltage condition said low side switch follows said comparator output.
4 more elements
A synchronous buck converter, comprising:
- at least one switching section with a high side switch and a low side switch, said switching section providing a voltage output;
- a pulse width modulating section coupled to said switching section and regulating said voltage output;
- and
- an over voltage protection section comprising a hysteresis comparator, said comparator having a first input coupled to a threshold over voltage reference and a second input coupled to an output voltage sensing network, a latch with a latch input is coupled to an output of said comparator wherein an output of said latch latches said high side switch and wherein said low side switch is electrically coupled to said output of said comparator without coupling through said latch.
1 more element
A method for over voltage protection for a synchronous buck converter, comprising:
- sensing an output voltage of a switching section of said buck converter, said switching section having a high side switch and a low side switch;
- comparing said sensed output voltage to a threshold voltage to determine an over voltage condition;
- upon said over voltage condition, latching said high side switch Off, and turning said low side switch On;
- and
- turning said low side switch Off when said sensed output voltage is below a low threshold voltage for said over voltage protection.
2 more elements
Dependencies are inferred from the claim text.