TWI642271B - Power operational amplifier with overcurrent protection mechanism and analog circuit system using the same - Google Patents

Abstract

A power operational amplifier with an overcurrent protection mechanism, comprising: an operational amplifier; a PMOS transistor; an NMOS transistor; and a first temperature dependent voltage limiting circuit having a voltage input terminal coupled to a supply voltage, And a voltage output terminal coupled to the gate of the PMOS transistor; and a second temperature dependent voltage limiting circuit having a voltage input terminal coupled to the supply voltage, and a voltage output terminal coupled to the NMOS a gate of the transistor is coupled; when the operating temperature exceeds a first temperature, the first temperature-dependent voltage limiting circuit begins to increase the voltage of the voltage output terminal thereof, and the second temperature-dependent voltage limiting circuit begins to decrease The voltage at the voltage output terminal, and when the operating temperature reaches a second temperature, the first temperature-dependent voltage limiting circuit causes the voltage at the voltage output terminal to reach a maximum value, and the second temperature-dependent voltage limiting The circuit will bring the voltage at the voltage output to a minimum.

Description

Power operational amplifier with overcurrent protection mechanism and analog circuit system using the same

This case relates to a power operational amplifier, in particular to a power operational amplifier with an overcurrent protection mechanism.

Please refer to FIG. 1, which illustrates an application circuit diagram of a conventional power operational amplifier. As shown in FIG. 1, a power operational amplifier 10 includes an operational amplifier 11, a PMOS transistor 12, and an NMOS transistor 13, which are powered by a supply voltage V _DD and generate an output according to an input voltage V _in. The voltage Vout is used to drive a load capacitor 20.

In many applications, the load capacitor 20 has a large capacitance value, generally several uF or more than ten uF. When the input voltage V _{in is} input with high and low potential signals, the output voltage Vout will follow the input voltage V _{in to} transform the potential, thereby continuously charging and discharging the load capacitor 20. If the operational amplifier 11 does not have an overcurrent protection circuit, the following problems may arise: Since the V _DD voltage is generally between ten and twenty volts, if the potential conversion frequency of the input voltage V _in is relatively high at this time The temperature of the power operational amplifier 10 will increase due to the increase in power consumption. If it continues to work, the power operational amplifier 10 will burn out.

There are two known solutions to the phenomenon of wafer burning.

Solution one: control the source-gate potential difference (Vsg) of the PMOS transistor 12 and the gate-source potential difference (Vgs) of the NMOS transistor 13 in FIG. 1 so that they are limited after increasing to a certain value No longer continue to increase, thereby limiting the maximum current flowing through the PMOS transistor 12 and NMOS transistor 13. In this method, the limit value of the source-gate potential difference of the PMOS transistor 12 and the limit value of the gate-source potential difference of the NMOS transistor 13 are independent of the size of V _DD , that is, no matter how large V _{DD is} , PMOS The source-gate potential difference limit value of the transistor 12 and the gate-source potential difference limit value of the NMOS transistor 13 are both kept fixed. The disadvantage of this method is that even when V _{DD is} at low voltage, the current of PMOS transistor 12 and NMOS transistor 13 will still be limited. Therefore, although PMOS transistor 12 and NMOS transistor 13 have high power specifications, The inability to provide greater current reduces not only the efficiency of use but also the speed of work. In fact, when the V _DD voltage is relatively small, even if the PMOS transistor 12 and the NMOS transistor 13 are not restricted, the power consumption of the power operational amplifier 10 is not high and will not be burned out.

Solution two: When the V _DD voltage is low, the source-gate potential difference (Vsg) of the PMOS transistor 12 and the gate-source potential difference (Vgs) of the NMOS transistor 13 are not limited; when the V _DD voltage reaches a certain value At this time, the source-gate potential difference (Vsg) of the PMOS transistor 12 and the gate-source potential difference (Vgs) of the NMOS transistor 13 are started to be controlled so that the temperature of the power operational amplifier 10 no longer rises by current limiting. However, the second solution still has its disadvantages: if the potential conversion frequency of the input voltage V _in is high, even if the source-gate potential difference (Vsg) of the PMOS transistor 12 and the gate-source potential difference of the NMOS transistor 13 are limited, (Vgs), the power operational amplifier 10 will continue to heat until it burns out; and if the potential conversion frequency of the input voltage V _in is relatively low, even if the V _DD voltage is relatively large, the temperature of the power operational amplifier 10 will not be too high, which is obviously limited The source-gate potential difference (Vsg) of the PMOS transistor 12 and the gate-source potential difference (Vgs) of the NMOS transistor 13 are superfluous.

In order to solve the above problems, a novel power operational amplifier structure is urgently needed in the art.

One of the objectives of this case is to provide a power operational amplifier with an overcurrent protection mechanism, which can regulate the source-gate potential difference of a PMOS transistor and the gate-source potential difference of an NMOS transistor according to its own temperature. Provides different current driving capabilities under different self-temperature conditions, thereby ensuring the safe operation of the power operational amplifier and optimizing the use efficiency of the power operational amplifier.

Another object of this case is to provide a power operational amplifier with an overcurrent protection mechanism, which can ensure the safe operation of the power operational amplifier and the use efficiency of the power operational amplifier by a simple, robust, and reliable temperature-dependent voltage limiting circuit. optimize.

To achieve the above purpose, a power operational amplifier with an overcurrent protection mechanism is proposed, which has:

An operational amplifier having a positive input terminal, a negative input terminal, a positive output terminal and a negative output terminal;

A PMOS transistor has a source, a gate, and a drain. The source is used for coupling with a supply voltage. The gate is coupled with the positive output terminal. The drain is used for A load coupling;

An NMOS transistor has a drain, a gate, and a source. The drain is used for coupling with the load. The gate is coupled with the negative output terminal. The source is used for A ground potential coupling;

A first temperature-dependent voltage limiting circuit having a voltage input terminal, a voltage output terminal, and a ground terminal. The voltage input terminal is used for coupling with the supply voltage, and the voltage output terminal is connected to the PMOS transistor. The gate is coupled, and the ground terminal is used for coupling with the ground potential; and

A second temperature-dependent voltage limiting circuit has a voltage input terminal, a voltage output terminal, and a ground terminal. The voltage input terminal is used for coupling with the supply voltage, and the voltage output terminal is connected to the NMOS transistor. The gate is coupled, and the ground terminal is used for coupling with the ground potential;

Wherein, during operation, the first temperature-dependent voltage limiting circuit starts to increase the voltage of the voltage output terminal after the temperature of the power operational amplifier with overcurrent protection mechanism exceeds a first temperature, and When the temperature of the power operational amplifier with an overcurrent protection mechanism reaches a second temperature, the voltage at the voltage output terminal reaches a maximum value; and the second temperature-dependent voltage limiting circuit is based on the overcurrent protection mechanism. After the temperature of the power operational amplifier exceeds the first temperature, the voltage of the voltage output terminal starts to decrease, and the voltage of the power operational amplifier with an overcurrent protection mechanism is brought to the voltage when the temperature reaches the second temperature. The voltage at the output reaches a minimum.

In an embodiment, the first temperature-dependent voltage limiting circuit has a first current-to-voltage conversion circuit to convert a first temperature-dependent current into a first temperature-dependent voltage, wherein the first temperature-dependent current is After the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, the current value is reduced to increase the first temperature-dependent voltage, and the first temperature-dependent current is at When the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, a minimum value is reached so that the first temperature-related voltage reaches a maximum value.

In one embodiment, the first current-to-voltage conversion circuit has:

A certain current source having a current input terminal to be coupled with the supply voltage, and a current output terminal to provide a certain current;

A first NMOS transistor has a drain, a gate, and a source. The drain is coupled to the current output terminal of the constant current source. The gate is coupled to the drain. The source is used for coupling with the ground potential;

A temperature-dependent current source has a current input terminal to be coupled to the current output terminal of the constant current source, and a current output terminal to be coupled to the ground potential, and is used to provide a temperature-dependent current to Causing the channel of the first NMOS transistor to generate the first temperature-dependent current;

A second NMOS transistor has a drain, a gate, and a source. The gate is coupled to the gate of the first NMOS transistor. The source is used to connect to the ground potential. Coupling; and

A resistor is coupled between the supply voltage and the drain of the second NMOS transistor to provide the first temperature-dependent voltage to drive a third NMOS transistor, wherein the third NMOS transistor The NMOS transistor has a drain, a gate, and a source. The drain is coupled to the supply voltage. The gate is coupled to the first temperature-dependent voltage. The source is used for Coupled with the gate of the PMOS transistor;

In operation, the temperature-dependent current source starts to increase the current value of the temperature-dependent current when the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, and When the temperature of the mechanism power operational amplifier reaches the second temperature, the temperature-dependent current reaches a current value of the constant current.

In one embodiment, the second temperature-dependent voltage-limiting circuit has a second current-to-voltage conversion circuit to convert a second temperature-dependent current into a second temperature-dependent voltage. After the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, the current operation value is lowered to reduce the second temperature-dependent voltage, and the second temperature-dependent current is When the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, a minimum value is reached so that the second temperature-dependent voltage reaches a minimum value.

In one embodiment, the second current-to-voltage conversion circuit has:

A certain current source has a current input terminal and a current output terminal, the current output terminal is coupled to the ground potential, and the constant current source is used to provide a certain current;

A first PMOS transistor having a source, a gate, and a drain. The source is used for coupling with the supply voltage, and the drain is coupled with the current input terminal of the constant current source. Connected, the gate is coupled with the drain;

A temperature-dependent current source having a current input terminal to be coupled to the supply voltage, and a current output terminal to be coupled to the current input terminal of the constant current source, and the temperature-dependent current source is used to provide A temperature-dependent current;

A second PMOS transistor has a source, a gate, and a drain. The gate is coupled to the gate of the first PMOS transistor. The source is used to connect to the supply voltage. Coupling; and

A resistor is coupled between the drain and the ground of the second PMOS transistor to provide the second temperature-dependent voltage to drive a third PMOS transistor. The third PMOS transistor The transistor has a source, a gate, and a drain. The source is used to couple with the gate of the NMOS transistor. The gate is connected to the drain of the second PMOS transistor. Coupling, the drain electrode is used for coupling with the ground potential;

In operation, the temperature-dependent current source starts to increase the current value of the temperature-dependent current when the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, and When the temperature of the mechanism power operational amplifier reaches the second temperature, the temperature-dependent current reaches a current value of the constant current.

In an embodiment, the first temperature-dependent voltage-limiting circuit has a first current-to-voltage conversion circuit to convert a first temperature-dependent current into a first temperature-dependent voltage. After the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, its current value is lowered to increase the first temperature-dependent voltage, and the first temperature-dependent current is in the The temperature of the power operational amplifier with an overcurrent protection mechanism reaches a minimum value when the second temperature reaches the second temperature so that the first temperature-dependent voltage reaches a maximum value; and the second temperature-dependent voltage limiting circuit has a first Two current-to-voltage conversion circuits to convert a second temperature-dependent current into a second temperature-related voltage, where the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature And then lowering its current value so that the second temperature-dependent voltage decreases its voltage value, and the second temperature-dependent current is at the overcurrent protection level. Reaches a minimum value when the temperature of the power operational amplifier mechanism reaches said second temperature to said second temperature-dependent voltage reaches a minimum.

In addition, the present invention also provides an analog circuit system, which has a power operational amplifier with an overcurrent protection mechanism as described above to provide a power driving function.

In order to make the reviewer of the Guigui better understand the structure, characteristics and purpose of this creation, the drawings and detailed description of the preferred embodiments are attached as follows.

Please refer to FIG. 2, which illustrates a block diagram of an embodiment of a power operational amplifier with an overcurrent protection mechanism according to the present invention. As shown in FIG. 2, a power operational amplifier 100 includes an operational amplifier 110, a PMOS transistor 120, an NMOS transistor 130, a first temperature-dependent voltage limiting circuit 140 and a second temperature-dependent voltage limiting circuit 150. .

The operational amplifier 110 has a positive input terminal, a negative input terminal, a positive output terminal gop, and a negative output terminal gon.

The PMOS transistor 120 has a source, a gate, and a drain. The source is used for coupling with a supply voltage V _DD . The gate is coupled with the positive output terminal gop. The drain is used for To be coupled to a load 200.

The NMOS transistor 130 has a drain, a gate, and a source. The drain is used to be coupled to the load 200. The gate is coupled to the negative output terminal gon. The source is used to Coupled to a ground potential.

The first temperature-dependent voltage limiting circuit 140 has a voltage input terminal, a voltage output terminal, and a ground terminal. The voltage input terminal is used for coupling with the supply voltage V _DD , and the voltage output terminal is connected with the PMOS transistor. The gate of 120 is coupled, and the ground terminal is used for coupling with the ground potential.

The second temperature-dependent voltage limiting circuit 150 has a voltage input terminal, a voltage output terminal, and a ground terminal. The voltage input terminal is used to be coupled to the supply voltage V _DD , and the voltage output terminal is connected to the NMOS transistor. The gate of 130 is coupled, and the ground terminal is used for coupling with the ground potential.

Wherein, during operation, the first temperature-dependent voltage limiting circuit 140 starts to increase the voltage of the voltage output terminal after the temperature of the power operational amplifier with overcurrent protection mechanism exceeds a first temperature. When the temperature of the power operational amplifier with overcurrent protection mechanism reaches a second temperature, the voltage at the voltage output terminal reaches a maximum value; and the second temperature-dependent voltage limiting circuit 150 is connected to the overcurrent After the temperature of the power operational amplifier of the protection mechanism exceeds the first temperature, the voltage of the voltage output terminal starts to decrease, and when the temperature of the power operational amplifier with the overcurrent protection mechanism reaches the second temperature, The voltage at the voltage output terminal reaches a minimum value.

Please refer to FIG. 3, which illustrates a circuit diagram of an embodiment of the first temperature-dependent voltage limiting circuit 140 of the power operational amplifier of FIG. 2. As shown in FIG. 3, the first temperature-dependent voltage limiting circuit 140 has a first current-to-voltage conversion circuit 141 and an NMOS transistor 142. The first current-to-voltage conversion circuit 141 is used to convert a first temperature-dependent current I _{O1 is} converted into a first temperature-dependent voltage V _O1 , wherein the first temperature-dependent current I _O1 starts to decrease its current value after the temperature of the power operational amplifier with overcurrent protection mechanism exceeds the first temperature In order to increase the voltage value of the first temperature-dependent voltage V _O1 , and the first temperature-dependent current I _O1 reaches a preset value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature. Set a value so that the first temperature-dependent voltage V _O1 reaches a maximum value.

The first current-to-voltage conversion circuit 141 includes a certain current source 141a, a first NMOS transistor 141b, a temperature-dependent current source 141c, a second NMOS transistor 141d, and a resistor 141e.

The constant current source 141a has a current input terminal to be coupled to the supply voltage V _DD and a current output terminal to provide a certain current I _REF .

The first NMOS transistor 141b has a drain, a gate, and a source. The drain is coupled to the current output terminal of the constant current source 141a, and the gate is coupled to the drain. The source is used for coupling with the ground potential.

The temperature-dependent current source 141c has a current input terminal to be coupled to the current output terminal of the constant current source 141a, and a current output terminal to be coupled to the ground potential, and is used to provide a temperature-dependent current I _T so that the channel of the first NMOS transistor 141b generates the first temperature-dependent current I _O1 .

The second NMOS transistor 141d has a drain, a gate, and a source. The gate is coupled to the gate of the first NMOS transistor 141b. The source is used to connect to the ground potential. Coupling.

The resistor 141e is coupled between the supply voltage V _DD and the drain of the second NMOS transistor 141d to provide the first temperature-dependent voltage V _O1 to drive a third NMOS transistor 142. The third NMOS transistor 142 has a drain, a gate, and a source. The drain is used for coupling with the supply voltage V _DD , and the gate is related to the first temperature-dependent voltage. V _{O1 is} coupled, and the source is coupled to the gate of the PMOS transistor 120. The voltage across the resistor 141e can be expressed as V _Ru = (I _REF -I _T ) * K * Ru, where K is the size ratio of the first NMOS transistor 141b and the second NMOS transistor 141d, and Ru is the resistance of the resistor 141e. value.

In addition, the maximum limiting potential difference between the source and the gate of the PMOS transistor 120 in FIG. 2 can be expressed as V _{sgP1_max} = V _Ru + V _gsN4 , where V _gsN4 is the potential difference between the gate and source of the third NMOS transistor 142. .

In operation, the temperature-dependent current source 141c starts to increase the current value of the temperature-dependent current I _T after the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature, and When the temperature of the power operational amplifier of the overcurrent protection mechanism reaches the second temperature, the temperature-dependent current I _T reaches the current value of the constant current I _REF . FIG. 4 illustrates a temperature function diagram of the temperature-dependent current I _T. As shown in Figure 4, I _T starts to rise when the temperature is about 85 ° C, and reaches I _REF when the temperature is about 160 ° C (this temperature can be adjusted according to the actual application). In general, the slope of the relationship between I _T and a temperature of not too much, and should be adjusted according to the chip package and the thermal environment and other factors. If the slope is too large, it is easy for the output current of the power operational amplifier to oscillate with temperature, and the output current becomes unstable. When the temperature is low, I _{T is} small and can be ignored, and the PMOS transistor 120 will not be limited by the current but can be completely turned on. When the temperature increases, I _T increases, V _{gsP1_max} becomes smaller, and the current flowing through the PMOS transistor 120 decreases. When the temperature is very high, such as over 160 ° C, I _T > I _REF , the gate potential of the third NMOS transistor 142 is equal to V _DD , and the current flowing through the PMOS transistor 120 is limited to a small value. Current value, so that the chip does not generate heat. In addition, preferably, V _DD <= I _REF * K * Ru can be ensured to ensure that the PMOS transistor 120 can be fully turned on when the operating temperature is lower than 85 ° C.

Please refer to FIG. 5, which illustrates a circuit diagram of an embodiment of the second temperature-dependent voltage limiting circuit 150 of the power operational amplifier of FIG. 2. As shown in FIG. 5, the second temperature-dependent voltage limiting circuit 150 has a second current-to-voltage conversion circuit 151 and a PMOS transistor 152. The second current-to-voltage conversion circuit 151 is used to correlate a second temperature. The current I _{O2 is} converted into a second temperature-dependent voltage V _O2 . The second temperature-dependent current I _O2 starts to reduce its current value after the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature. Reducing the second temperature-dependent voltage V _O2 to a voltage value, and the second temperature-dependent current I _O2 reaches a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature So that the second temperature-dependent voltage V _O2 reaches a minimum value.

The second current-to-voltage conversion circuit 151 includes a certain current source 151a, a first PMOS transistor 151b, a temperature-dependent current source 151c, a second PMOS transistor 151d, and a resistor 151e.

The constant current source 151a has a current input terminal and a current output terminal, the current output terminal is coupled to the ground potential, and the constant current source 151a is used to provide a certain current I _REF .

The first PMOS transistor 151b has a source, a gate, and a drain. The source is used to be coupled to the supply voltage V _DD . The drain is connected to the current of the constant current source 151a. The input terminal is coupled, and the gate is coupled to the drain.

The temperature-dependent current source 151c has a current input terminal to be coupled with the supply voltage V _DD , and a current output terminal is coupled to the current input terminal of the constant current source 151a, and the temperature-dependent current source 151c is It is used to provide a temperature-dependent current I _T , and its current-temperature relationship is shown in FIG. 4.

The second PMOS transistor 151d has a source, a gate, and a drain. The gate is coupled to the gate of the first PMOS transistor 151b. The source is used to connect to the supply voltage. V _{DD is} coupled.

The resistor 151e is coupled between the drain and the ground of the second PMOS transistor 151d to provide the second temperature-dependent voltage V _O2 to drive a third PMOS transistor 152. The third PMOS transistor 152 has a source, a gate, and a drain. The source is used to couple with the gate of the NMOS transistor 130. The gate is connected to the second PMOS transistor. The drain electrode of 151d is coupled, and the drain electrode is used for coupling with the ground potential.

During operation, the temperature-dependent current source 151c starts to increase the temperature-dependent current I after the temperature of the power operational amplifier with overcurrent protection mechanism exceeds the first temperature (for example, but not limited to 85 ° C). Current value of _T , and when the temperature of the power operational amplifier with overcurrent protection mechanism reaches the second temperature (for example, but not limited to 160 ° C), the temperature-dependent current I _T reaches the constant current I _REF current value. That is, when the temperature is low, I _{T is} small and can be ignored, and the PMOS transistor 120 will not be limited by the current and can be completely turned on; when the temperature increases, I _T increases, and the second temperature-dependent current I _O2 follows. It becomes smaller, so that the voltage across the resistor 151e becomes smaller, thereby reducing the current flowing through the NMOS transistor 130; when the temperature is very high, for example, exceeding 160 ° C, I _T > I _REF , the third PMOS voltage The gate potential of the crystal 152 is almost equal to the ground potential. At this time, the current flowing through the NMOS transistor 130 is limited to a small current value, and the chip can be prevented from being burned.

With the design disclosed above, the present invention has the following advantages:

1. The power operational amplifier with overcurrent protection mechanism of the present invention can regulate the source-gate potential difference of a PMOS transistor and the gate-source potential difference of an NMOS transistor according to its own temperature to Provides different current driving capabilities under temperature conditions, thereby ensuring safe operation of the power operational amplifier and optimizing the use efficiency of the power operational amplifier.

2. The power operational amplifier with overcurrent protection mechanism of the present invention can ensure the safe operation of the power operational amplifier and optimize the use efficiency of the power operational amplifier by a simple, strong and reliable temperature-dependent voltage limiting circuit.

The one disclosed in this case is one of the preferred embodiments, and any change or modification that originates from the technical ideas of this case and is easily inferred by those who are familiar with the technology, does not depart from the scope of patent rights in this case.

10, 100‧‧‧ Power Operational Amplifier

11, 110‧‧‧ operational amplifier

12, 120, 152‧‧‧PMOS transistors

13, 130, 142‧‧‧‧ NMOS transistors

20‧‧‧Load capacitance

140‧‧‧First temperature-dependent voltage limiting circuit

141‧‧‧First current-to-voltage conversion circuit

141a, 151a‧‧‧Constant current source

141b‧‧‧The first NMOS transistor

141c, 151c‧‧‧‧ temperature-dependent current source

141d‧‧‧Second NMOS transistor

141e, 151e‧‧‧ resistance

150‧‧‧Second temperature-dependent voltage limiting circuit

151‧‧‧Second current-to-voltage conversion circuit

151b‧‧‧The first PMOS transistor

151d‧‧‧Second PMOS transistor

200‧‧‧ load

FIG. 1 illustrates an application circuit diagram of a conventional power operational amplifier. FIG. 2 is a block diagram of an embodiment of a power operational amplifier with an overcurrent protection mechanism according to the present invention. FIG. 3 is a circuit diagram of an embodiment of a first temperature-dependent voltage limiting circuit of the power operational amplifier of FIG. 2. FIG. 4 is a temperature function diagram of a temperature-dependent current of a first temperature-dependent voltage limiting circuit of FIG. 3. FIG. 5 is a circuit diagram of an embodiment of a second temperature-dependent voltage limiting circuit of the power operational amplifier of FIG. 2.

Claims (9)

A power operational amplifier with an overcurrent protection mechanism includes: an operational amplifier having a positive input terminal, a negative input terminal, a positive output terminal, and a negative output terminal; a PMOS transistor having a source electrode, a A gate electrode and a drain electrode, the source electrode is used for coupling with a supply voltage, the gate electrode is coupled with the positive output terminal, and the drain electrode is used for coupling with a load; an NMOS transistor having A drain electrode, a gate electrode and a source electrode, the drain electrode is used for coupling with the load, the gate electrode is coupled with the negative output terminal, and the source electrode is used for coupling with a ground potential; A first temperature-dependent voltage limiting circuit having a voltage input terminal, a voltage output terminal, and a ground terminal. The voltage input terminal is used for coupling with the supply voltage, and the voltage output terminal is connected to the PMOS transistor. The gate is coupled, the ground terminal is used for coupling with the ground potential; and a second temperature-dependent voltage limiting circuit having a voltage input terminal, a voltage output terminal and a ground terminal, the voltage input terminal Is used to supply electricity Coupled, the voltage output terminal is coupled with the gate of the NMOS transistor, and the ground terminal is used for coupling with the ground potential; wherein, during operation, the first temperature-dependent voltage limiting circuit system After the temperature of the power operational amplifier with overcurrent protection mechanism exceeds a first temperature, the voltage of the voltage output terminal starts to increase, and the temperature of the power operational amplifier with overcurrent protection mechanism reaches a second temperature. When the voltage at the voltage output terminal reaches a maximum value; and the second temperature-dependent voltage limiting circuit starts to reduce the temperature of the power operational amplifier with an overcurrent protection mechanism after the temperature exceeds the first temperature The voltage of the voltage output terminal is caused to reach a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature. The power operational amplifier with an overcurrent protection mechanism according to item 1 of the scope of patent application, wherein the first temperature-dependent voltage limiting circuit has a first current-to-voltage conversion circuit to convert a first temperature-dependent current Into a first temperature-dependent voltage, wherein the first temperature-dependent current starts to decrease its current value after the temperature of the power operational amplifier with overcurrent protection mechanism exceeds the first temperature to make the first temperature The relevant voltage increases its voltage value, and the first temperature-dependent current reaches a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, so that the first temperature-dependent voltage reaches A maximum. The power operational amplifier with an overcurrent protection mechanism according to item 2 of the patent application scope, wherein the first current-to-voltage conversion circuit has: a certain current source having a current input terminal for coupling with the supply voltage And a current output terminal to provide a certain current; a first NMOS transistor having a drain, a gate, and a source, the drain is coupled to the current output of the constant current source, and A gate is coupled to the drain, and the source is used to couple with the ground potential; a temperature-dependent current source having a current input terminal to be coupled to the current output terminal of the constant current source, And a current output terminal coupled to the ground potential and configured to provide a temperature-dependent current so that the channel of the first NMOS transistor generates the first temperature-dependent current; a second NMOS transistor, A drain electrode, a gate electrode, and a source electrode, the gate electrode is coupled to the gate electrode of the first NMOS transistor, and the source electrode is used to couple with the ground potential; and a resistor Is coupled between the supply voltage and the drain of the second NMOS transistor to provide the first temperature-dependent voltage to drive a third NMOS transistor, wherein the third NMOS transistor The crystal has a drain, a gate, and a source. The drain is coupled to the supply voltage. The gate is coupled to the first temperature-dependent voltage. The source is coupled to The gate of the PMOS transistor is coupled; in operation, the temperature-dependent current source starts to increase the temperature-dependent current after the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature. A current value of the current value, and when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, the temperature-dependent current reaches the current value of the constant current. The power operational amplifier with an overcurrent protection mechanism according to item 1 of the patent application scope, wherein the second temperature-dependent voltage limiting circuit has a second current-to-voltage conversion circuit to convert a second temperature-dependent current Into a second temperature-dependent voltage, the second temperature-dependent current starts to decrease the current value of the power operational amplifier with an overcurrent protection mechanism after the temperature exceeds the first temperature to make the second temperature-dependent voltage Reduce its voltage value, and the second temperature-dependent current reaches a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature so that the second temperature-dependent voltage reaches a minimum value. The power operational amplifier with an overcurrent protection mechanism according to item 4 of the scope of the patent application, wherein the second current-to-voltage conversion circuit has: a certain current source having a current input terminal and a current output terminal, and the current The output terminal is coupled to the ground potential, and the constant current source is used to provide a certain current. A first PMOS transistor has a source, a gate, and a drain. The source is used to communicate with The supply voltage is coupled, the drain is coupled to the current input terminal of the constant current source, and the gate is coupled to the drain electrode; a temperature-dependent current source has a current input terminal to communicate with all The supply voltage is coupled, and a current output terminal is coupled to the current input terminal of the constant current source, and the temperature-dependent current source is used to provide a temperature-dependent current; a second PMOS transistor having a A source, a gate, and a drain, the gate is coupled to the gate of the first PMOS transistor, and the source is used to couple with the supply voltage; and a resistor Is coupled between the drain and the ground of the second PMOS transistor to provide the second temperature-dependent voltage to drive a third PMOS transistor, wherein the third PMOS transistor has A source, a gate, and a drain, the source is used for coupling with the gate of the NMOS transistor, and the gate is coupled with the drain of the second PMOS transistor, The drain electrode is used for coupling with the ground potential. During operation, the temperature-dependent current source starts to increase the temperature after the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature. The current value of the correlation current, and when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, the temperature-dependent current reaches the current value of the constant current. The power operational amplifier with an overcurrent protection mechanism according to item 1 of the scope of patent application, wherein the first temperature-dependent voltage limiting circuit has a first current-to-voltage conversion circuit to convert a first temperature-dependent current Into a first temperature-dependent voltage, the first temperature-dependent current starts to decrease the current value of the power operational amplifier with an overcurrent protection mechanism after the temperature exceeds the first temperature, so that the first temperature-dependent voltage The voltage value is increased, and the first temperature-dependent current reaches a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, so that the first temperature-dependent voltage reaches a maximum And the second temperature-dependent voltage limiting circuit has a second current-to-voltage conversion circuit to convert a second temperature-dependent current into a second temperature-dependent voltage, the second temperature-dependent current is After the temperature of the power operational amplifier of the current protection mechanism exceeds the first temperature, its current value is reduced to reduce the second temperature-dependent voltage. Its voltage value is low, and the second temperature-dependent current reaches a minimum value when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, so that the second temperature-dependent voltage reaches a minimum value. The power operational amplifier with an overcurrent protection mechanism according to item 6 of the patent application scope, wherein the first current-to-voltage conversion circuit has: a certain current source having a current input terminal for coupling with the supply voltage And a current output terminal to provide a certain current; a first NMOS transistor having a drain, a gate, and a source, the drain is coupled to the current output of the constant current source, and A gate is coupled to the drain, and the source is used to couple with the ground potential; a temperature-dependent current source having a current input terminal to be coupled to the current output terminal of the constant current source, And a current output terminal coupled to the ground potential and configured to provide a temperature-dependent current so that the channel of the first NMOS transistor generates the first temperature-dependent current; a second NMOS transistor, Having a drain, a gate, and a source, the gate is coupled to the gate of the first NMOS transistor, and the source is used to couple with the ground potential; and a resistor, Is coupled between the supply voltage and the second NMOS transistor To provide a first temperature-dependent voltage between the drains to drive a third NMOS transistor, wherein the third NMOS transistor has a drain, a gate, and a source, the drain Is used for coupling with the supply voltage V _DD , the gate is coupled with the first temperature-related voltage, and the source is used for coupling with the gate of the PMOS transistor; during operation The temperature-dependent current source starts to increase the current value of the temperature-dependent current after the temperature of the power operational amplifier with the over-current protection mechanism exceeds the first temperature, and When the temperature of the operational amplifier reaches the second temperature, the temperature-dependent current reaches a current value of the constant current. The power operational amplifier with an overcurrent protection mechanism according to item 6 of the patent application scope, wherein the second current-to-voltage conversion circuit has: a certain current source having a current input terminal and a current output terminal, and the current The output terminal is coupled to the ground potential, and the constant current source is used to provide a certain current. A first PMOS transistor has a source, a gate, and a drain. The source is used to communicate with The supply voltage is coupled, the drain is coupled to the current input terminal of the constant current source, and the gate is coupled to the drain electrode; a temperature-dependent current source has a current input terminal to communicate with all The supply voltage is coupled, and a current output terminal is coupled to the current input terminal of the constant current source, and the temperature-dependent current source is used to provide a temperature-dependent current; a second PMOS transistor having a A source, a gate, and a drain, the gate is coupled to the gate of the first PMOS transistor, and the source is used to couple with the supply voltage; and a resistor Is coupled between the drain and the ground of the second PMOS transistor to provide the second temperature-dependent voltage to drive a third PMOS transistor, wherein the third PMOS transistor has A source, a gate, and a drain, the source is used for coupling with the gate of the NMOS transistor, and the gate is coupled with the drain of the second PMOS transistor, The drain electrode is used for coupling with the ground potential. During operation, the temperature-dependent current source starts to increase the temperature after the temperature of the power operational amplifier with an overcurrent protection mechanism exceeds the first temperature. The current value of the correlation current, and when the temperature of the power operational amplifier with an overcurrent protection mechanism reaches the second temperature, the temperature-dependent current reaches the current value of the constant current. An analog circuit system includes a power operational amplifier with an overcurrent protection mechanism as described in any one of claims 1 to 8 of the patent application scope to provide a power driving function.