High voltage level translator
First Claim
1. A circuit for controlling a capacitive load, comprising:
- an N-channel FET having a gate electrode, a drain electrode coupled to a high voltage signal source Vpp, wherein Vpp comprises a positive going pulse train, and a source electrode coupled to an output Vcntrl for controlling the load; and
a charging circuit, responsive to a low voltage input signal Vpp_sel, for charging the FET gate to a bias voltage greater than the FET gate'"'"'s threshold voltage while Vpp is near zero volts and for maintaining the bias voltage on the FET gate while Vpp ramps up to a value greater than the bias voltage and until Vpp_sel is removed.
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Accused Products
Abstract
A circuit for controlling a piezoelectric transducer includes an N-channel FET having a gate electrode, a drain electrode coupled to a high voltage signal source Vpp, wherein Vpp is a positive going pulse train, and a source electrode coupled to an output Vcntrl for controlling the transducer and a charging circuit, responsive to a low voltage input signal Vpp_sel, for charging the FET gate to a bias voltage greater than the FET'"'"'s threshold voltage while Vpp is near zero volts and for maintaining the bias voltage on the FET gate while Vpp ramps up to a value greater than the bias voltage and until Vpp_sel is removed. The control circuit reduces switching time and reduces current spikes in the power supplies to the chip.
15 Citations
22 Claims
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1. A circuit for controlling a capacitive load, comprising:
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an N-channel FET having a gate electrode, a drain electrode coupled to a high voltage signal source Vpp, wherein Vpp comprises a positive going pulse train, and a source electrode coupled to an output Vcntrl for controlling the load; and a charging circuit, responsive to a low voltage input signal Vpp_sel, for charging the FET gate to a bias voltage greater than the FET gate'"'"'s threshold voltage while Vpp is near zero volts and for maintaining the bias voltage on the FET gate while Vpp ramps up to a value greater than the bias voltage and until Vpp_sel is removed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A circuit for controlling a capacitive load, comprising:
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an N-channel FET having a gate electrode, a source electrode coupled to a high voltage signal source Vss, wherein Vss comprises a negative going pulse train, and a drain electrode coupled to an output Vcntrl for controlling the load; a charging circuit, responsive to a low voltage input signal Vss_sel, for charging the FET gate to a bias voltage greater than the FET'"'"'s threshold voltage while Vss is near zero volts and for maintaining the bias voltage on the FET gate until Vss_sel is removed; a charge removal circuit, responsive to removal of Vss_sel, for removing the charge on the FET gate such that no substantial DC current is drawn from Vcntrl; wherein the charging circuit comprises a P-channel FET (Q14) having a gate electrode driven by Vss_sel, a source electrode coupled to an intermediate voltage source, and a drain electrode coupled to the gate of the N-channel FET.
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12. A circuit for controlling a capacitive load, comprising:
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an N-channel FET having a gate electrode, a drain electrode coupled to a high voltage signal source Vpp, wherein Vpp comprises a positive going pulse train, and a source electrode coupled to an output Vcntrl for controlling the load; and a gate control circuit, for controlling the voltage on the FET gate, wherein the gate control circuit includes a charging circuit, responsive to a low voltage input signal Vpp_sel, for providing a bias voltage greater than Vpp to the FET gate while Vpp is near zero volts and for maintaining the bias voltage on the FET gate until Vpp_sel is removed, and a discharging circuit, responsive to removal of the low voltage input signal, for removing charge from the FET gate such that no substantial DC current is drawn from Vcntrl. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification