Charge pump load determination circuit
AssigneeSipex Corporation
InventorsPaul S. Chan, Raymond Chow, Henry K. Wong
Life of this patent
Estimating the term…
Abstract
Circuit and method for determining the presence of a load in a circuit including on a charge pump. The circuit monitors the state of a pump signal indicative of the operating status of the charge pump. The circuit generates a signal indicating the presence or absence of a load. The signal is used to deactivate features of an associated device, thereby reducing the power consumption and extending the life of the power supply (e.g., battery) for the device.
Claims9
A circuit for determining the presence of a load comprising:
- a charge pump having a pump signal terminal for providing a pump signal indicative of an operating state of the charge pump, the pump signal having a duty cycle indicative of the time the pump signal is in a first state;
- and
- a monitor module having a monitor input terminal in electrical communication with the pump signal terminal, and a monitor output terminal, the monitor module providing at the monitor output terminal a status signal indicative of the presence of the load in the circuit in response to the duty cycle of the pump signal, wherein the monitor module comprises a comparator having a first comparator input terminal in electrical communication with the monitor input terminal, a second comparator input terminal adapted to receive a first reference voltage, and a comparator output terminal in electrical communication with the monitor output terminal.
A method for determining the presence of a load in a circuit having a charge pump, comprising:
- (a) receiving a pump signal indicative of the operating state of the charge pump;
- (b) determining a duty cycle of the pump signal;
- and
- (c) determining whether a load is present in the circuit in response to the duty cycle wherein step (c) comprises:
- filtering the pump signal to generate a filtered signal having a substantially DC voltage, the filtered signal being substantially proportional to a time average of the pump signal;
- and
- comparing the filtered signal to a reference voltage.
Dependencies are inferred from the claim text.