Transistor substrate dynamic biasing circuit
AssigneeSTMicroelectronics S.r.l.
InventorsJulien Le Coz, Alexandre Valentian, Philippe Flatresse, Sylvain Engels
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Abstract
A dynamic biasing circuit of the substrate of a MOS power transistor may include a first switch configured to connect the substrate to a current source which forward biases the intrinsic source-substrate diode of the transistor, when the gate voltage of the transistor turns the transistor on. The current source may include a stack of diodes in the same conduction direction as the intrinsic diode between the substrate and a supply voltage.
Claims10
A dynamic biasing circuit for a substrate of a metal oxide semiconductor (MOS) power transistor to be coupled to power an electronic function block on or off, the MOS power transistor comprising an intrinsic source-substrate diode, the dynamic biasing circuit comprising:
- a current source;
- a first switch configured to couple the substrate to said current source so that the intrinsic source-substrate diode is forward biased when a gate voltage of the MOS power transistor turns the MOS power transistor on;
- said current source comprising a stack of diodes between the substrate and a supply voltage and having a same conduction direction as the intrinsic source-substrate diode;
- and
- interrupt circuitry configured to interrupt current in said stack of diodes when the electronic function block is inactive based upon an associated output signal and when the MOS power transistor is on.
An integrated circuit comprising:
- a substrate;
- a power transistor on said substrate and to be coupled to power an electronic function block on or off, the MOS power transistor having an intrinsic source-substrate diode;
- a current source between said substrate and a supply voltage, and comprising a stack of diodes;
- a first switch configured to couple said substrate to said current source so that the intrinsic source-substrate diode is forward biased when a control terminal voltage of the power transistor turns the power transistor on;
- and
- interrupt circuitry configured to interrupt current in said stack of diodes when the electronic function block is inactive based upon an associated output signal and when the power transistor is on.
A biasing method for a substrate of a metal oxide semiconductor (MOS) power transistor coupled to power an electronic function block on or off, the MOS power transistor comprising an intrinsic source-substrate diode, the method comprising:
- using a first switch to couple the substrate to a current source so that the intrinsic source-substrate diode is forward biased when a gate voltage of the MOS power transistor turns the MOS power transistor on;
- the current source comprising a stack of diodes between the substrate and a supply voltage and having a same conduction direction as the intrinsic source-substrate diode;
- and
- using interrupt circuitry to interrupt current in the stack of diodes when the electronic function block is inactive based upon an associated output signal and when the MOS power transistor is on.
Dependencies are inferred from the claim text.