Method and system for controlling HS-NMOS power switches with slew-rate limitation
First Claim
1. A method for controlling an array of power switches with slew-rate limit, comprising the following steps:
- (1) providing an array of HS-NMOS power switches comprising a multitude of switch driver cells each controlling a correspondent power switch, and a charge pump;
(2) limiting slew rate of the power switch;
(3) deploying only one charge pump for the total array of power switches, wherein the charge pump is isolated from the multitude of switch drivers; and
(4) establishing zero current draw from the charge pump in case of a steady state of a power switch;
wherein said zero current in steady state is established by steps of;
sampling a gate voltage of the power switch when power switch is enabled;
turning gate of power switch fully ON;
thenreducing all currents drawn from the charge pump for the correspondent driver cell to zero; and
latch the state of previous step until a control signal goes low and then high again.
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Abstract
A method and system for limiting the slew rate of the output voltage of one or more high side (HS) NMOS power switches is disclosed. A circuit arrangement configured to control a first NMOS switch is described. The arrangement comprises voltage provisioning means configured to supply a gate voltage to a gate terminal of the first NMOS switch; current provisioning means configured to provide a current; a first control stage configured to provide and/or remove a connection between the gate terminal of the first NMOS switch and the voltage provisioning means, thereby switching the first NMOS switch to an on-state and/or an off-state, respectively; and a first feedback control link between an output terminal of the first NMOS switch and the current provisioning means configured to control the slew-rate of a voltage at the first output terminal.
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Citations
6 Claims
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1. A method for controlling an array of power switches with slew-rate limit, comprising the following steps:
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(1) providing an array of HS-NMOS power switches comprising a multitude of switch driver cells each controlling a correspondent power switch, and a charge pump; (2) limiting slew rate of the power switch; (3) deploying only one charge pump for the total array of power switches, wherein the charge pump is isolated from the multitude of switch drivers; and (4) establishing zero current draw from the charge pump in case of a steady state of a power switch; wherein said zero current in steady state is established by steps of; sampling a gate voltage of the power switch when power switch is enabled; turning gate of power switch fully ON;
thenreducing all currents drawn from the charge pump for the correspondent driver cell to zero; and latch the state of previous step until a control signal goes low and then high again. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification