Controlled charge pump arrangement and method for controlling a clocked charge pump
AssigneeAms AG
InventorPramod Singnurkar
Life of this patent
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Abstract
A controlled charge pump comprises a clock operated charge pump having an output terminal to provide an output voltage. A first sub-circuit is coupled to the output terminal of the clocked operated charge pump and adapted to provide a first control signal in response to a comparison of the output voltage with a first reference signal. A second sub-circuit is coupled to the clocked operated charge pump and provides a second control signal in response to a comparison of a switch current within the clocked operated charge pump with a second reference signal. A clock skip controller is adapted to control the mode of operation of the clocked operated charge pump in response to that first and second control signals.
Claims14
A controlled charge pump arrangement, comprising:
- a clocked operated charge pump having an output terminal to provide an output voltage;
- a first sub-circuit coupled to the output terminal of the clocked operated charge pump and adapted to provide a first control signal in response to a comparison of the output voltage with a first reference signal;
- a second sub-circuit coupled to the clocked operated charge pump and adapted to provide a second control signal in response to a comparison of a signal with a second reference signal, said signal being different from the output voltage and derived by a switch current within the clocked operated charge pump;
- and
- a clock skip controller adapted to control a mode of operation of the clocked operated charge pump in response to said first and second control signals,
- wherein the second sub-circuit comprises a current mirror, its current mirror transistor coupled to the charge pump switch to mirror a current through the switch and an equalizing network, said equalizing network comprising a differential amplifier connected to said charge pump switch and to a sensing transistor, said charge pump switch and sensing transistor receiving the same switching signal.
A method for controlling a clocked charge pump, said charge pump comprising an operation mode out of a first mode and a second mode, wherein in the first mode the clocked charge pump is operated continuously with respect to a clock signal and in the second mode the clocked charge pump is operated non-continuously with respect to the clock signal such that driving pulses for the clocked charge pump are not generated during one or more skipped periods of the clock signal, the method comprising:
- sensing an output voltage of the clocked charge pump;
- comparing the output voltage with a first reference signal to provide a first control signal;
- sensing a switching current of the charge pump during operation of the clocked charge pump;
- comparing the switching current or a signal different from the output voltage and derived from the switching current with a second reference signal to provide a second control signal;
- and
- changing an operation mode of the clocked charge pump in response to the first and/or second control signals,
- wherein changing the operation mode comprises at least one of the following:
- initiating a transition from the first mode to the second mode when the switching current or a signal derived from the switching current is smaller than the second reference signal;
- initiating a transition from the second mode to the first mode when the switching current or a signal derived from the switching current is greater than the second reference signal;
- initiating a transition from the second mode to the first mode when an output voltage during the second mode is smaller than the second reference signal;
- and
- initiating a transition from the second mode to the first mode when an output voltage during the second mode is smaller than an output voltage during the preceding continuous mode.
Dependencies are inferred from the claim text.