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US 9,000,690 B2Granted
Driver for capacitive loads
AssigneeTexas Instruments Incorporated
InventorsMayank Garg, David J. Baldwin, Boqiang Xiao
Life of this patent
Estimating the term…
Abstract
A method for driving a piezoelectric transducer is provided. An input signal is received. At least one of a plurality of modes is selected for a buck-boost stage from a comparison of a desired voltage on a capacitor to a first threshold and a second threshold, where the desired voltage is determined from the input signal. The piezoelectric transducer is then driven substantially within the audio band using the desired voltage on the capacitor using an H-bridge that changes state with each zero-crossing.
Claims10
An apparatus comprising:
- a host processor;
- a cell;
- a capacitor that is coupled to the cell;
- an inductor;
- a piezoelectric transducer;
- and
- a piezoelectric driver having:
- an input terminal that is coupled to the host processor;
- a supply terminal;
- a first switching terminal;
- a second switching terminal, wherein the first and second switching terminals are configured to be coupled to an inductor;
- a boost terminal that is configured to be coupled to a capacitor;
- a first output terminal;
- a second output terminal, wherein the first and second output terminals are configured to be coupled to a piezoelectric transducer;
- a first H-bridge that is coupled to the supply terminal, the boost terminal, the first switching terminal, and the second switching terminal;
- a second H-bridge that is coupled to the boost terminal, the first output terminal, and the second output terminal;
- and
- a control circuit that is coupled to control the first and second H-bridges, wherein the control circuit is configured to operate the first H-bridge as a buck-boost circuit, and wherein the control circuit is configured to operate the first and second H-bridges to drive substantially within the audio band.
15 more elements
An apparatus comprising:
- a host processor;
- a cell;
- a capacitor that is coupled to the cell;
- an inductor;
- a piezoelectric transducer;
- and
- a piezoelectric driver having:
- an input terminal that is coupled to the host processor;
- a first supply terminal that is coupled to the cell;
- a second supply terminal that is coupled to the cell;
- a first switching terminal that is coupled to the inductor;
- a second switching terminal that is coupled to the inductor;
- a boost terminal that is coupled to the capacitor;
- a first output terminal that is coupled to the piezoelectric transducer;
- a second output terminal that is coupled to the piezoelectric transducer;
- a first H-bridge that is coupled to the first supply terminal, the second supply terminal, the boost terminal, the first switching terminal, and the second switching terminal;
- a second H-bridge that is coupled to the boost terminal, the second supply terminal, the first output terminal, and the second output terminal;
- and
- a control circuit that is coupled to control the first and second H-bridges, wherein the control circuit is configured to operate the first H-bridge as a buck-boost circuit, and wherein the control circuit is configured to operate the first and second H-bridges to drive substantially within the audio band.
16 more elements
Dependencies are inferred from the claim text.