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US 6,605,982 B2Granted
Bias circuit for a transistor of a storage cell
AssigneeSTMicroelectronics S.r.l.
InventorMichael J. Callahan, Jr.
Life of this patent
Estimating the term…
Abstract
An integrated circuit includes storage circuits comprising isolation transistors to which a certain bias voltage may be applied. The bias voltage is generated by a bias voltage generator. A boost circuit responds to initial bias voltage transition by generating a boost current that is applied to the isolation transistors with the transitioning bias voltage.
Claims34
A transistor bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage to a control terminal of at least one transistor;
- a reference voltage generator that generates an output voltage responsive to a first transition in the control signal;
- and
- a voltage follower having an input connected to receive the output voltage from the reference voltage generator and an output connected to the bias circuit output, the voltage follower operating in transient conditions with respect to the output bias voltage to source a boost current at its output to rapidly charge the bias circuit output;
- wherein the bias circuit output applies the output bias voltage and the boost current to bias up the at least one transistor.
3 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator that generates an output voltage responsive to a first transition in the control signal;
- a voltage follower having an input connected to receive the output voltage from the reference voltage generator and an output connected to the bias circuit output, the voltage follower operating in transient conditions with respect to the output bias voltage to source a boost current at its output to rapidly charge the bias circuit output;
- and
- a first protection circuit operating responsive to a second transition in the control signal to pull the input of the voltage follower to ground.
3 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator that generates an output voltage responsive to a first transition in the control signal;
- and
- a voltage follower having an input connected to receive the output voltage from the reference voltage generator and an output connected to the bias circuit output, the voltage follower operating in transient conditions with respect to the output bias voltage to source a boost current at its output to rapidly charge the bias circuit output, wherein the voltage follower comprises a source follower configured transistor.
2 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator that generates an output voltage responsive to a first transition in the control signal;
- a voltage follower having an input connected to receive the output voltage from the reference voltage generator and an output connected to the bias circuit output, the voltage follower operating in transient conditions with respect to the output bias voltage to source a boost current at its output to rapidly charge the bias circuit output;
- and
- a current source connected between the voltage follower output and ground.
3 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator that generates an output voltage responsive to a first transition in the control signal;
- a voltage follower having an input connected to receive the output voltage from the reference voltage generator and an output connected to the bias circuit output, the voltage follower operating in transient conditions with respect to the output bias voltage to source a boost current at its output to rapidly charge the bias circuit output;
- and
- a storage circuit including an isolation transistor having a gate and a floating gate transistor;
- wherein the bias circuit output is connected to the gate of the isolation transistor for applying the output bias voltage and the boost current to the storage circuit.
4 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage to a control terminal of at least one transistor;
- a reference voltage generator connected to the bias circuit output that generates the output bias voltage responsive to a first transition in the control signal;
- and
- a source follower having an input connected to receive an indication of output bias voltage generation by the reference voltage generator and an output connected to the bias circuit output, the source follower operating responsive to the indication to source a boost current at its output to rapidly charge the bias circuit output;
- wherein the bias circuit output applies the output bias voltage and the boost current to bias up the at least one transistor.
3 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator connected to the bias circuit output that generates the output bias voltage responsive to a first transition in the control signal;
- a source follower having an input connected to receive an indication of output bias voltage generation by the reference voltage generator and an output connected to the bias circuit output, the source follower operating responsive to the indication to source a boost current at its output to rapidly charge the bias circuit output;
- and
- a first protection circuit operating responsive to a second transition in the control signal to pull the input of the source follower to ground.
3 more elements
A bias circuit receiving a control signal, comprising:
- an input connected to receive the control signal;
- a bias circuit output for applying an output bias voltage;
- a reference voltage generator connected to the bias circuit output that generates the output bias voltage responsive to a first transition in the control signal;
- a source follower having an input connected to receive an indication of output bias voltage generation by the reference voltage generator and an output connected to the bias circuit output, the source follower operating responsive to the indication to source a boost current at its output to rapidly charge the bias circuit output;
- and
- a storage circuit including an isolation transistor having a gate and a floating gate transistor;
- wherein the bias circuit output is connected to the gate of the isolation transistor for applying the output bias voltage and the boost current to the storage circuit.
4 more elements
An apparatus for rapidly charging a transistor control terminal which may have substantial capacitance associated therewith, said apparatus comprising:
- a voltage reference generator;
- a current driving stage;
- wherein said current driving stage operates in a class AB manner to allow high current upon demand to bias up the transistor control terminal while still allowing for low quiescent current.
A transistor bias circuit receiving a control signal, comprising:
- a bias voltage generator including an input connected to receive the control signal and an output, the bias voltage generator producing an output voltage signal that transitions from a first value to a second value in response to a change in the control signal;
- a boost circuit operating responsive to the transition of the output voltage signal from the first value to generate a boost current;
- and
- means for combining the output voltage signal and the boost current as an output bias voltage for application to a control terminal of at least one transistor for the purpose of biasing up that transistor.
1 more element
A bias circuit receiving a control signal, comprising:
- a bias voltage generator including an input connected to receive the control signal and an output, the bias voltage generator producing a voltage signal that transitions from a first value to a second value in response to a change in the control signal;
- a boost circuit operating responsive to the transition of the voltage signal from the first value to generate a boost current;
- means for combining the voltage signal and the boost current as an output bias voltage;
- and
- a protection circuit operating responsive to the control signal to pull the boost circuit to ground;
- wherein the boost circuit comprises a transistor having a control gate, the protection circuit pulling the control gate of the transistor to ground.
3 more elements
A method for generating a transistor bias voltage, comprising the steps of:
- generating a bias voltage output signal that transitions from a first value to a second value in response to a change in a control signal;
- applying the bias voltage output signal to a control terminal of a transistor;
- detecting transition of the bias voltage output signal from the first value;
- generating a boost current in response to the detected transition in the bias voltage output signal;
- and
- applying the boost current in combination with the bias voltage output signal and thus rapidly achieve the output bias voltage at the control terminal of the transistor.
3 more elements
Apparatus for rapidly charging a control terminal of a transistor to a bias voltage, the apparatus employing a bias driver, the bias driver comprising:
- a voltage reference generator;
- an input receiving a control signal;
- a current driver circuit;
- wherein the control signal is effective to either activate or deactivate the bias driver, and when activated, the current driver operating to charge the capacitive line to a desired bias voltage responsive to said voltage reference generator with an amount of current greater than its quiescent value in order to achieve a rapid charging of said transistor control terminal.
1 more element
A transistor control terminal biasing circuit, comprising:
- a bias voltage generator responsive to an input signal and having an output terminal to which an output bias voltage is supplied, the output terminal for connection to a transistor control terminal;
- and
- a boost current generator configured for feedback loop operation to sense voltage transitions at the output terminal and respond to a sensed voltage transition changing from about zero volts by supplying relatively large amounts of boost current to the output terminal and further respond to a sensed voltage transition approaching a target bias voltage by reducing the boost current supplied to the output terminal.
A method for transistor control terminal biasing, comprising the steps of:
- generating an output bias voltage in response to an input signal for application to a transistor control terminal;
- sensing voltage transitions in the output bias voltage;
- responding to a sensed voltage transition changing from about zero volts by supplying relatively large amounts of boost current for application with the output bias voltage to the transistor control terminal;
- and
- responding to a sensed voltage transition approaching a target bias voltage by reducing the amount of boost current supplied to the transistor control terminal.
2 more elements
Dependencies are inferred from the claim text.