High voltage integrated circuit driver for half-bridge circuit employing a bootstrap diode emulator
First Claim
1. A circuit for driving a half-bridge formed by lower and upper power transistors connected between an output terminal and respective lower and upper rails of a high voltage DC supply, and for charging a bootstrap capacitor having first and second ends, the first end being connected to said output terminal, said circuit comprising:
- controller and level shifter means for generating lower and upper drive command signals for commanding driving said respective lower and upper power transistors to noncontemporaneous conducting states;
power supply means for generating at a power supply output a relatively low control voltage with respect to said lower rail;
a lower drive module connected to the power supply output for being powered by said relatively low control voltage and comprising means for applying a lower drive control signal between a control electrode of the lower power transistor and the lower rail in response to said lower drive command signal;
an upper drive module adapted to be connected to the first end of the bootstrap capacitor for being powered by a bootstrap voltage across said bootstrap capacitor and comprising means for applying an upper transistor control signal between a control electrode of the upper power transistor and the output terminal in response to said upper drive input control signal; and
bootstrap diode emulator means for charging said bootstrap capacitor to said bootstrap voltage, said bootstrap diode emulator means comprising a further transistor having a high current first electrode connected to said power supply output, a high current second electrode adapted to be connected to the second end of the bootstrap capacitor and a control third electrode coupled to a further control signal derived from said lower drive command signal for driving said further transistor to a conducting state when the lower power transistor is driven to a conducting state.
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Accused Products
Abstract
A half-bridge driver circuit including a lower drive module and a floating upper drive module for driving respective external upper and lower power transistors of a high voltage half bridge is contained in an integrated circuit chip which includes an on-chip bootstrap diode emulator for charging an external bootstrap capacitor that powers the upper drive module. The upper drive is accommodated in an insulated well and the diode emulator includes as its main current carrying element, a LDMOS transistor formed along the periphery of the well. The LDMOS transistor is driven into a conducting state at the same time the lower power transistor is driven into a conducting state.
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Citations
10 Claims
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1. A circuit for driving a half-bridge formed by lower and upper power transistors connected between an output terminal and respective lower and upper rails of a high voltage DC supply, and for charging a bootstrap capacitor having first and second ends, the first end being connected to said output terminal, said circuit comprising:
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controller and level shifter means for generating lower and upper drive command signals for commanding driving said respective lower and upper power transistors to noncontemporaneous conducting states; power supply means for generating at a power supply output a relatively low control voltage with respect to said lower rail; a lower drive module connected to the power supply output for being powered by said relatively low control voltage and comprising means for applying a lower drive control signal between a control electrode of the lower power transistor and the lower rail in response to said lower drive command signal; an upper drive module adapted to be connected to the first end of the bootstrap capacitor for being powered by a bootstrap voltage across said bootstrap capacitor and comprising means for applying an upper transistor control signal between a control electrode of the upper power transistor and the output terminal in response to said upper drive input control signal; and bootstrap diode emulator means for charging said bootstrap capacitor to said bootstrap voltage, said bootstrap diode emulator means comprising a further transistor having a high current first electrode connected to said power supply output, a high current second electrode adapted to be connected to the second end of the bootstrap capacitor and a control third electrode coupled to a further control signal derived from said lower drive command signal for driving said further transistor to a conducting state when the lower power transistor is driven to a conducting state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification