Operational amplifier circuit and overcurrent protection method thereof

Abstract

The embodiment of the invention discloses an operational amplifier circuit and an overcurrent protection method thereof. The operational amplifier circuit comprises: a control unit used for generatingan output control signal according to an input signal and an output signal; an output unit used for generating output current under the action of the output control signal, wherein the output unit comprises an output capacitor, and the output capacitor is charged or discharged by the output current to generate the output signal; and an overcurrent protection unit used for obtaining temperature control current according to the working temperature of the operational amplifier circuit, wherein when the working temperature is greater than or equal to a set temperature, the temperature control current is positively correlated with the working temperature, and the overcurrent protection unit adjusts the output control signal according to the temperature control current to limit the output current. According to the operational amplifier circuit disclosed by the invention, the temperature control current is obtained by detecting the working temperature, when the working temperature is withina reasonable range, the output efficiency, the response speed and the driving capability of the operational amplifier circuit are ensured, and when the working temperature is too high, the output current is limited according to the temperature control current to reduce the circuit power consumption and the working temperature.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to an operational amplifier circuit and an overcurrent protection method thereof. Background technique [0002] In many applications, an operational amplifier (Operation Amplifier, OPA) needs to drive a large load capacitance, and the capacitance of the load capacitance is generally several microfarads to tens of microfarads. [0003] figure 1 An operational amplifier circuit 100 in the prior art is shown, wherein the operational amplifier U0 generates an output control signal according to the input signal Vin0 and the fed back output signal Vout0, and the output control signal controls the transistor P0 or the transistor N0, so that the output capacitor Cout0 is continuously The output current Iout0 provided by the pull-up transistor or the pull-down transistor is charged and discharged, and then an output voltage Vout0 is provided on its upper plate. [0004] General...

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Problems solved by technology

However, the disadvantage of this prior art is that the magnitude of the output current cannot be controlled according to the frequency of the input signal. When the frequency of the input signal is low, even if the high power supply voltage VDD is high, the gate-source voltage of the transistors P0 and N0 are also high , the power consumption and operating temperature of the operational amplifier circuit will not be too high, so it is not necessary to limit the gate-source voltage of transistors P0 and N0 at this time; at the same time, if the frequency of the input signal is high, then even if the transistor P0 and The gate-source voltage of N0, the power consumption and operating temperature of the operational amplifier circuit will also increase

[0008] Therefore, in order to solve the problem of the operating temperature of the operational amplifier circuit, there are certain limitations in the prior art

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