Charge pump circuit and methods of operation thereof
AssigneeWolfson Microelectronics plc
InventorDouglas James Wallace MacFarlane
Life of this patent
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Abstract
A method of generating a voltage supply (Vout+, Vout−) from a single input supply (+VDD), comprising connecting at least one flying capacitor (Cf) to at least one reservoir capacitor (CR1, CR2) and to the input supply in repeated cycles so as to generate a voltage on said reservoir capacitor, the cycles differing between at least two modes so that each mode generates a different voltage on said reservoir capacitor the method including changing from an existing one of said modes to enter a new one of said modes during operation, and operating in at least one transitional mode for a period prior to entering fully said new mode.
Claims33
A charge pump circuit having terminals for connection to an input voltage supply, first and second reservoir capacitors, a flying capacitor and a switch array interconnecting said terminals, the circuit being operable, in use, in an equalization mode to repeatedly alternate said flying capacitor between a connection to said first reservoir capacitor and a connection to said second reservoir capacitor without connecting the flying capacitor to the input voltage supply, the circuit being further operable, in use, in at least:
- a first voltage generating mode to generate first output voltages on said first and second reservoir capacitors;
- and
- a second voltage generating mode to generate second output voltages on said first and second reservoir capacitors,
- wherein the first output voltages are lower in magnitude than the second output voltages.
A charge pump comprising:
- a switch array which is interposed among first and second output capacitors, a flying capacitor, and an input power supply;
- and
- a controller which controls the switch array, wherein
- the charge pump is operable in an operation mode including a high-voltage outputting mode, a low-voltage outputting mode, and an equalization mode, and
- the controller controls the switch array so that:
- in the high-voltage outputting mode, the first and second output capacitors respectively output first positive and negative voltages;
- in the low-voltage outputting mode, the first and second output capacitors respectively output second positive and negative voltages lower than the first positive and negative voltages;
- and
- in the equalization mode, respective charging voltages of the first and second capacitors that are charged in the high-voltage outputting mode are gradually lowered, and
- the controller changes the operation mode of the charge pump by direct transition from the low-voltage outputting mode to the high-voltage outputting mode when a voltage raise command is given during a period when the operation mode of the charge pump is in the low-voltage outputting mode, and
- the controller changes the operation mode of the charge pump by transition from the high-voltage outputting mode through the equalization mode to the low-voltage outputting mode when a voltage lower command is given during a period when the operation mode of the charge pump is in the high-voltage outputting mode.
A charge pump circuit having terminals adapted for connection to an input voltage supply, first and second reservoir capacitors and at least one flying capacitor, the circuit being operable, in use, in a mode where said at least one flying capacitor is connected in a sequence of states such that the voltages on the first and second reservoir capacitors gradually lower and remain substantially balanced.
A charge pump circuit for producing positive and negative output voltages operable, in use, in:
- a first mode to produce positive and negative output voltages of a first magnitude,
- a second mode to produce positive and negative output voltages of a second magnitude, the first magnitude being lower than the second magnitude;
- and
- a third mode to allow the output voltages to reduce from the second magnitude towards the first magnitude whilst ensuring the positive and negative voltages remain substantially balanced.
Dependencies are inferred from the claim text.