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US 2013/0257521 A1Published application
Controlling over voltage on a charge pump power supply node
AssigneeApple Inc.
InventorsTaif A. Syed, Sang Y. Youn
Life of this patent
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Abstract
A charge pump driver circuit has a first charge switch that couples a first node of a flying capacitor to a first power supply node, and a second charge switch that couples a second node of the capacitor to a second power supply node. Control circuitry is coupled to open the second charge switch and discharge the second node of the capacitor, in response to a control signal. Other embodiments are also described and claimed.
Claims19
1-9. (canceled)
A method for alleviating overvoltage on a charge pump power supply node, comprising:
- generating a power control signal, which signifies that first and second power supply nodes may be powered down, wherein the first and second power supply nodes are to be selectively connected by a charge pump driver circuit to first and second nodes, respectively, of a flying capacitor;
- and
- in response to generating the power control signal, disconnecting the second power supply node from the second node of the capacitor and then discharging the second node of the capacitor, wherein during power down, following discharging of the second node of the capacitor, the negative power supply voltage goes to zero before the positive power supply voltage drops to zero.
(canceled)
An electronic system comprising:
- a controller having first and second power supply nodes, the controller having control logic that is to generate a power control signal that requests an external power supply circuit to power down the first and second power supply nodes;
- a flying capacitor;
- a charge pump driver circuit having a first charge switch that couples a first node of the capacitor to the first power supply node, and a second charge switch that couples a second node of the capacitor to the second power supply node;
- and
- control circuitry that is coupled to open the second charge switch and discharge the second supply node, in response to the power control signal.
2 more elements
Dependencies are inferred from the claim text.