Circuit for ensuring full saturation of amplifiers of a single input configured bridge amplifier
AssigneeSTMicroelectronics S.r.l.
InventorsDavide Brambilla, Giovanni Capodivacca
Life of this patent
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Abstract
A circuit for ensuring a complete saturation of both operational amplifiers of a single-input bridge amplifier is provided. A voltage divider is connected between the inverting inputs of the two amplifiers and a saturation current signal is injected on the intermediate node of the voltage divider. Such a saturation current signal is obtained through dedicated sensing devices of the state of saturation reached by the transistors of the output stages of both amplifiers of the single-input bridge amplifier.
Claims20
A bridge amplifier comprising:
- a first operational amplifier and a second operational amplifier connected in a single-input configuration and a noninverting input of the second operational amplifier connected to a reference, each of the first and second operational amplifiers including an output stage having at least two transistors;
- a first feedback resistor connecting an output of the first operational amplifier to an inverting input of the first operational amplifier;
- a second feedback resistor connecting an output of the second operational amplifier to an inverting input of the second operational amplifier;
- a resistive voltage divider being connected between the inverting inputs of the first and second operational amplifiers and having an intermediate node;
- a first pair of sensors for sensing a state of saturation of the transistors of the output stage of the first operational amplifier;
- and
- a second pair of sensors for sensing a state of saturation of the transistors of the output stage of the second operational amplifier;
- outputs of the first and second pairs of sensors being summed at the intermediate node of the resistive voltage divider.
A bridge amplifier comprising:
- a first operational amplifier and a second operational amplifier, a noninverting input of the second operational amplifier connected to a reference, and each of the first and second operational amplifiers including an output stage having at least one transistor;
- a voltage divider being connected between inverting inputs of the first and second operational amplifiers and having an intermediate node;
- and
- at least one sensor for sensing a state of saturation of the at least one transistor of each output stage, an output of the at least one sensor being connected to the intermediate node of the voltage divider.
A method of operating a bridge amplifier comprising a first operational amplifier and a second operational amplifier, a noninverting input of the second operational amplifier connected to a reference, and each of the first and second operational amplifiers including an output stage having at least one transistor, a first feedback resistor connects an output of the first operational amplifier to an inverting input of the first operational amplifier, a second feedback resistor connects an output of the second operational amplifier to an inverting input of the second operational amplifier, the method comprising the steps of:
- providing a voltage divider between the inverting inputs of the first and second operational amplifiers;
- sensing a state of saturation of the at least one transistor of the output stages of the first and second operational amplifiers;
- and
- providing the sensed state of saturation to an intermediate node of the voltage divider.
A method of ensuring full saturation of first and second operational amplifiers of a single-input configured bridge amplifier comprising the steps of:
- sensing the state of saturation of at least one transistor of an output stage of the first operational amplifier;
- sensing the state of saturation of at least one transistor of an output stage of the second operational amplifier;
- and
- summing the sensed states of saturation at an intermediate node of a voltage divider connected between inverting inputs of the first and second operational amplifiers.
A method of making a bridge amplifier comprising the steps of:
- providing a first operational amplifier and a second operational amplifier, a noninverting input of the second operational amplifier connected to a reference, and each of the first and second operational amplifiers including an output stage having at least one transistor;
- connecting a voltage divider between inverting inputs of the first and second operational amplifiers and defining an intermediate node therebetween;
- providing at least one sensor for sensing a state of saturation of the at least one transistor of the output stages of the first and second operational amplifiers;
- and
- connecting an output of the sensor to the intermediate node of the voltage divider.
Dependencies are inferred from the claim text.