TWI484316B - Voltage generator and bandgap reference circuit - Google Patents

Description

Voltage generator and bandgap reference circuit

The present invention relates to a voltage generator and a bandgap reference circuit, and more particularly to a voltage generator and a bandgap reference circuit having a small layout area and suitable for implementing a high-accuracy reference voltage.

Analogous circuit applications often use a stable reference voltage source or current source that is unaffected by temperature changes to provide a reference or reference current to monitor the correct operation of the power supply or other circuits, and a bandgap reference circuit (Bandgap Reference) Circuit) is such a circuit. Briefly, the bandgap reference circuit mixes a positive to absolute temperature (PTAT) current/voltage with a negative to absolute temperature (CTAT) current/voltage in an appropriate ratio. After the positive temperature coefficient and the negative temperature coefficient are offset each other, a zero temperature coefficient current/voltage is generated.

In detail, please refer to FIG. 1 , which is a schematic diagram of an energy band gap reference circuit 10 in the prior art. The bandgap reference circuit 10 includes an operational amplifier 100, bipolar transistors Q1, Q2, and resistors R1 R R3. As shown in FIG. 1, in the bandgap reference circuit 10, the input voltages VX and VY of the positive and negative input terminals of the operational amplifier 100 are equal (VX=VY=VEB1, and VEB1 is the base emitter voltage of the bipolar transistor Q1). The voltage difference between the voltage VY and VZ (ie, VEB2) (ie, VY-VZ) and the resistor R3 can generate a positive temperature coefficient current Iptat, as shown in equation (1): Wherein, K indicates that the bipolar transistor Q2 can be regarded as being formed by connecting K bipolar transistors Q1 in parallel. Since the thermal voltage V _T is a positive temperature coefficient, the positive temperature coefficient current Iptat carried by the resistor R3 is a positive temperature coefficient from the equation (1).

Since the base emitter voltage VEB2 of the bipolar transistor Q2 has a negative temperature coefficient, Vout represents the bandgap reference voltage output by the bandgap reference circuit 10 at its output, as shown in equation (2): Among them, it can be known from the formula (2) that the values of K, R2, and R3 can be appropriately selected. Zero, whereby the bandgap reference voltage Vout is zero temperature coefficient voltage.

However, the conventional bandgap reference circuit uses a bipolar transistor for temperature compensation, usually requires a higher power supply voltage and a larger reference voltage, resulting in higher static power loss and cannot be effectively applied. In a lower supply voltage environment, at the same time, the circuit using the dual carrier transistor also greatly increases the layout area. therefore, The industry proposes a complementary band gap reference circuit with a complementary metal oxide semiconductor (CMOS) for temperature compensation. However, the negative temperature coefficient voltage generated by this circuit varies greatly with the process, and the zero temperature coefficient is generated. The voltage accuracy will also become lower, which is not conducive to use. In view of this, the prior art has been improved.

Accordingly, it is a primary object of the present invention to provide a voltage generator and a bandgap reference circuit.

The invention discloses a voltage generator comprising a first transistor, a second transistor, an operational amplifier, a capacitor, a third transistor, a fourth transistor and a first resistor. The first transistor includes a first end coupled to a voltage source, and a second end coupled to the third end; the second transistor includes a first end coupled to the voltage source, and a first The second end is coupled to the third end; the operational amplifier includes a first input coupled to the second end and the third end of the first transistor, and a second input coupled to the second The second end of the crystal and the third end, and an output end; the capacitor includes a first end coupled to the output end of the operational amplifier, and a second end coupled to a ground end; the third end The transistor includes a first end coupled to the third end of the first transistor, a second end coupled to the output end of the operational amplifier and the first end of the capacitor, and a third end; The fourth transistor includes a first end coupled to the third end of the second transistor, a second end coupled to the output end of the operational amplifier and the first end of the capacitor, and a first end The three ends are coupled to the ground end; and the first resistor is coupled to the ground Between the third end of the third transistor and the ground end, a negative temperature coefficient voltage is generated according to a voltage difference between a gate source voltage of the third transistor and a gate source voltage of the fourth transistor .

The invention further discloses an energy bandgap reference circuit comprising a positive temperature coefficient current source, a negative temperature coefficient voltage generator and a zero temperature coefficient voltage generator. The positive temperature coefficient current source is used to generate a positive temperature coefficient current; the negative temperature coefficient voltage generator comprises a first transistor, a second transistor, an operational amplifier, a capacitor, a third transistor, and a first Four transistors and a first resistor. The first transistor includes a first end coupled to a voltage source, and a second end coupled to the third end; the second transistor includes a first end coupled to the voltage source, and a first The second end is coupled to the third end; the operational amplifier includes a first input coupled to the second end and the third end of the first transistor, and a second input coupled to the second The second end of the crystal and the third end, and an output end; the capacitor includes a first end coupled to the output end of the operational amplifier, and a second end coupled to a ground end; the third end The transistor includes a first end coupled to the third end of the first transistor, a second end coupled to the output end of the operational amplifier and the first end of the capacitor, and a third end; The fourth transistor includes a first end coupled to the third end of the second transistor, a second end coupled to the output end of the operational amplifier and the first end of the capacitor, and a first end The third end is coupled to the ground end; and the first resistor is coupled between the third end of the third transistor and the ground end, and is used Generating a negative temperature coefficient voltage according to a voltage difference between a gate source voltage of the third transistor and a gate source voltage of the fourth transistor; and the zero temperature coefficient voltage generator is coupled to the positive temperature coefficient current source With the negative temperature coefficient voltage generator In between, it is used to add a positive temperature coefficient voltage and a negative temperature coefficient voltage to generate a zero temperature coefficient voltage.

Please refer to FIG. 2A. FIG. 2A is a schematic diagram of a complementary to absolute temperature (CTAT) voltage generator 20 according to an embodiment of the present invention. The negative temperature coefficient voltage generator 20 includes transistors M1 to M4, an operational amplifier 200, a capacitor C, and a resistor R4. As shown in FIG. 2A, the operational amplifier 200 includes an input coupled to the transistor M1 and another input coupled to the transistor M2. The operational amplifier 200 is configured to generate a control signal based on the signal received at its input to control the operation of the transistors M3, M4. The capacitor C is coupled between the output end of the operational amplifier 200 and a ground terminal. The transistor M3 is coupled to the output of the transistor M1 and the operational amplifier 200. The transistor M4 is coupled to the output of the transistor M2 and the operational amplifier 200 and the ground. Among them, the transistors M3 and M4 are N-type gold oxide half field effect transistors. The resistor R4 is coupled between the transistor M3 and the ground for generating a negative temperature coefficient voltage according to a voltage difference between the gate and source voltages of the transistors M3 and M4. For example, as shown in FIG. 2A, the voltage difference V _R4 across the resistor R4 is equal to the voltage difference between the gate source voltage of the transistor M3 and the gate source voltage of the transistor M4. The voltage difference V _R4 across the resistor R4 is the negative temperature coefficient voltage.

Briefly, the negative temperature coefficient voltage generator 20 of the present invention can generate the negative temperature coefficient voltage required for the bandgap reference circuit based on the gate-to-source voltage difference of the transistors M3, M4. That is to say, the negative temperature coefficient voltage generator 20 does not need to use the double carrier electron crystal The body can produce a high-precision negative temperature coefficient voltage while greatly reducing the circuit layout area.

In detail, the transistor M1 is coupled to one input terminal of the operational amplifier 200, and the transistor M2 is coupled to the other input terminal of the operational amplifier 200. Thereby, the operational amplifier 200 can be input according to the transistors M1 and M2. The signal generates a control signal to control the transistors M3 and M4 to operate in the subcritical region. Preferably, the transistors M3, M4 are different types of gold oxide half field effect transistors, such that the threshold voltage of the transistor M3 is different from the threshold voltage of the transistor M4. Further, when the transistors M3 and M4 have different threshold voltages and operate in the subcritical region at the same time, according to the current-voltage (IV) characteristics of the transistors, the gate-source voltage difference of the transistors M3 and M4 is substantially It will be equal to the critical voltage difference of the transistors M3, M4. The following will be explained step by step by the arithmetic formulas (3) and (4). When the transistors M3, M4 are operated in the subcritical region and the threshold voltages of the transistors M3, M4 are greater than four times the thermal voltage V _T , the current-voltage characteristics of the transistors M3 and M4 are respectively as shown in the equation (3). :

Among them, I _{D_M3} and I _{D_M4} are the drain currents of the transistors M3 and M4 respectively, μ is the groove electron mobility, V _{GS_M3} and V _{GS_M4} are the gate and source voltages of the transistors M3 and M4, respectively, V _{th_M3} , V _{th_M4} They are the threshold voltages of the transistors M3 and M4, respectively, m is the subcritical region slope factor, and W/L is the width to length ratio of the transistor. When I _{D_M3} = I _{D_M4} and (W/L) ₃ = (W/L) ₄ , the expression (3) can be expressed as the following expression (4):

In other words, it can be seen from equation (4) that in the case where the transistors M3, M4 operate in the subcritical region and the threshold voltage of the transistors M3, M4 is greater than four times the thermal voltage V _T , the gate source of the transistor M3 The voltage difference between the voltage and the gate-to-source voltage of the transistor M4 may be equal to the voltage difference between the threshold voltage of the transistor M3 and the threshold voltage of the transistor M4.

Furthermore, as shown in FIG. 2A, the voltage difference V _R4 across the resistor R4 is the voltage difference between the gate-source voltage of the transistor M3 and the gate-source voltage of the transistor M4. Therefore, it can be seen from the relationship of the formula (4) that the voltage difference V _R4 across the resistor R4 is equal to the voltage difference between the threshold voltage of the transistor M3 and the threshold voltage of the transistor M4. The threshold voltage of the transistors M3 and M4 is a negative temperature coefficient voltage. Therefore, the voltage difference V _R4 across the resistor _R4 is also a negative temperature coefficient voltage, and the current passing through the resistor R4 is a negative temperature coefficient current Ictat'. In short, different types of transistors have different threshold voltages and temperature coefficients in the same environment. The present invention utilizes different types of transistors to implement the transistors M3, M4, which in turn produces a negative temperature coefficient voltage that varies less with process. That is, the negative temperature coefficient voltage generator 20 of the present invention will produce a high accuracy negative temperature coefficient voltage based on the threshold voltage difference of the transistors M3, M4 operating in the subcritical region.

Please refer to FIG. 2B. FIG. 2B is a comparison diagram of negative temperature coefficient voltages of the negative temperature coefficient voltage generator 20 at different temperatures and processes according to the second embodiment of the present invention. Among them, TT, FF and SS are different process environments well known to those skilled in the art, and will not be described here. It can be seen from FIG. 2B that the negative temperature coefficient voltage is generated according to the threshold voltage difference of the transistors M3 and M4 operating in the subcritical region, and the negative temperature coefficient voltage generator 20 can indeed achieve high accuracy requirements, and more importantly, Meet the space constraints of circuit applications.

It is worth noting that the main spirit of the present invention is to generate a negative temperature coefficient voltage by using the threshold voltage difference of the transistors M3 and M4 to achieve high accuracy requirements. Among them, the transistors M3 and M4 are different types of N-type gold oxide half field effect transistors, for example, the threshold voltage of the transistor M4 (such as 442 mV) is higher than the threshold voltage of the transistor M3 (such as 340 mV), and The transistors M3, M4 have different temperature coefficients. Further, the transistors M1, M2 are P-type gold oxide half field effect transistors, and the operational amplifier 200 can be composed of different transistors. For example, the operational amplifier 200 can include a P-type MOS field effect transistor and an N-type MOS field effect transistor. It can be seen from the above that the circuit structure of the negative temperature coefficient voltage generator of the present invention is mainly composed of a gold oxide half field effect transistor and a resistor and the transistors M3 and M4 are operated in the subcritical region, whereby the negative temperature coefficient voltage is generated. The required supply voltage VCC is low (down to 1V), which in turn reduces power loss.

On the other hand, the negative temperature coefficient voltage generator 20 of the present invention can be applied to a circuit that generates a zero temperature (zero-temperature) voltage. Example For example, please refer to FIG. 3A. FIG. 3A is a schematic diagram of a bandgap reference circuit 30 according to an embodiment of the present invention. The bandgap reference circuit 30 includes a positive temperature coefficient current source 300, a negative temperature coefficient voltage generator 302, and a zero temperature coefficient voltage generator 304. The positive temperature coefficient current source 300 is used to generate a positive temperature coefficient current Iptat'. The negative temperature coefficient voltage generator 302 is used to generate a negative temperature coefficient voltage and generate a negative temperature coefficient current Ictat' based on the negative temperature coefficient voltage. The method in which the negative temperature coefficient voltage generator 302 generates the negative temperature coefficient voltage is substantially similar to the negative temperature coefficient voltage generator 20, and details are not described herein again. Further, the structure of the negative temperature coefficient voltage generator 302 is similar to that of the negative temperature coefficient voltage generator 20, so the same elements follow the same symbols. The negative temperature coefficient voltage generator 302 differs from the negative temperature coefficient voltage generator 20 in that the negative temperature coefficient voltage generator 302 replaces the operational amplifier 200 with an operational amplifier 306. The operational amplifier 306 is a structural diagram of an embodiment of the operational amplifier 200, but is not limited thereto. The zero temperature coefficient voltage generator 304 is coupled between the positive temperature coefficient current source 304 and the negative temperature coefficient voltage generator 302 for generating a zero temperature coefficient reference voltage according to the positive temperature coefficient current Iptat' and the negative temperature coefficient voltage. Vref. In this case, the bandgap reference circuit 30 can generate high accuracy based on the positive temperature coefficient current Iptat' generated by the positive temperature coefficient current source 304 and the negative temperature coefficient current Ictat' generated by the negative temperature coefficient voltage generator 302. The zero temperature coefficient voltage of the degree is compared with the conventional band gap reference circuit using the bipolar transistor for temperature compensation. The invention can effectively reduce the layout area and reduce the power supply voltage VCC to achieve low power loss. . It is to be noted that the band gap reference circuit 30 of FIG. 3A is merely illustrative of one of the present invention, and those skilled in the art can modify or change the present invention without departing from the scope of the present invention.

Further, the operation of the bandgap reference circuit 30 will be explained step by step by current and voltage analysis. The zero temperature coefficient voltage generator 304 includes a current mirror M9 and resistors R5, R6. As shown in FIG. 3A, the voltage difference across the resistor R4 of the negative temperature coefficient voltage generator 302 is a negative temperature coefficient voltage, and the passing current is a negative temperature coefficient current Ictat'. The current mirror M9 is used to replicate the negative temperature coefficient current Ictat' generated by the negative temperature coefficient voltage generator 302. The resistor R5 is coupled to the current mirror M9, and the resistor R6 is coupled to the resistor R5, the positive temperature coefficient current source 300, and the ground terminal for generating a positive temperature coefficient voltage. In this way, when the zero temperature coefficient voltage generator 304 receives the negative temperature coefficient current Ictat' copied by the current mirror M9 and the positive temperature coefficient current Iptat' generated by the positive temperature coefficient current source 300, the current can be based on the positive temperature coefficient. The positive temperature coefficient voltage generated by Iptat' and the negative temperature coefficient voltage generated according to the negative temperature coefficient current Ictat' produce a zero temperature coefficient voltage Vref, as shown in equation (5):

Among them, K _P is the positive temperature coefficient of the positive temperature coefficient current Iptat', and the negative temperature coefficient of the K _N system negative temperature coefficient current Ictat'. Therefore, by appropriately adjusting the resistors R5 and R6 to satisfy the equation (5), the zero temperature coefficient voltage Vref can be obtained. Therefore, the structure of the present invention can generate a high-accuracy zero temperature coefficient voltage without using a double carrier transistor, thereby effectively reducing the layout area and reducing the power loss. In addition, the present invention can achieve a high-accuracy voltage output that is not affected by temperature by different types of transistors operating simultaneously in the sub-critical region.

Please refer to FIG. 3B. FIG. 3B is a comparison diagram of the zero temperature coefficient voltage Vref of the bandgap reference circuit 30 at different temperatures and processes according to the third embodiment of the present invention. Among them, TT, FF and SS are different processes well known to those skilled in the art, and will not be described here. As shown in Figure 3B, when the temperature rises from -40 degrees to 125 degrees, the zero temperature coefficient voltage of the same process (such as the zero temperature coefficient voltage curve Vref_tt shown in Figure 3B) does not change much with temperature, but different processes The multiple zero temperature coefficient voltages in the environment (such as the zero temperature coefficient voltage curves Vref_ff, Vref_tt and Vref_ff shown in Figure 3B) do not change much from each other, that is, the zero temperature coefficient voltage changes with temperature and process variation. Not big. Therefore, the bandgap reference circuit 30 can regulate the zero temperature coefficient voltage Vref under temperature variation and process variation, thereby generating a high-accuracy zero temperature coefficient voltage.

It is to be noted that FIG. 3A is an illustration of the present invention, but is not limited thereto as long as the effect can be achieved. For example, the current mirror M9 is preferably a P-type gold-oxygen half field effect transistor, mainly for replicating a negative temperature coefficient current, but is not limited thereto. The positive temperature coefficient current source 300 can also be combined with other components to produce a positive temperature coefficient current. In addition, the resistance values of the resistors R4, R5, and R6 can also be different according to different embodiments. Adjust to meet the conditions of equation (5) to obtain the desired zero temperature coefficient voltage.

In summary, it is known that a negative temperature coefficient voltage generator using a bipolar transistor needs to use a higher power supply voltage, and the generated reference voltage is usually large, resulting in an ineffective application in a lower supply voltage environment. And must also consume a lot of power and layout area. In contrast, the negative temperature coefficient voltage generator of the present invention does not require the use of a bipolar transistor, and can be generated by a threshold voltage difference of a gold oxide half field effect transistor operating in a subcritical region and of a different type. The accuracy of the negative temperature coefficient voltage, in this way, can effectively reduce the layout area and greatly reduce power loss. At the same time, it is possible to achieve a high-accuracy voltage output that is immune to temperature.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10, 30‧‧‧ Bandgap reference circuit

100, 200, 306‧‧‧Operational Amplifier

20, 302‧‧‧Negative temperature coefficient voltage generator

300‧‧‧ positive temperature coefficient current source

304‧‧‧zero temperature coefficient voltage generator

R1~R6‧‧‧ resistor

Q1, Q2‧‧‧ double carrier transistor

VCC‧‧‧Power supply voltage

VX, VY, VZ, V _R4 ‧‧‧ voltage

Vout‧‧‧ Bandgap reference voltage

M1~M4‧‧‧Gold Oxygen Semiconductor

C‧‧‧ capacitor

Ictat’‧‧‧Negative temperature coefficient current

Iptat, Iptat’‧‧‧ positive temperature coefficient current

Vref‧‧‧ zero temperature coefficient reference voltage

M9‧‧‧current mirror

V_ff, V_tt, V_ss‧‧‧negative temperature coefficient voltage curve

Vref_ff, Vref_tt, Vref_ss‧‧‧ zero temperature coefficient voltage curve

Figure 1 is a schematic diagram of a conventional bandgap reference circuit.

2A is a schematic diagram of a negative temperature coefficient voltage generator according to an embodiment of the present invention.

FIG. 2B is a comparison diagram of the negative temperature coefficient voltages of the negative temperature coefficient voltage generators at different temperatures and processes according to the second embodiment of the present invention.

FIG. 3A is a schematic diagram of an energy band gap reference circuit according to an embodiment of the present invention.

FIG. 3B is a comparison diagram of zero temperature coefficient voltages of the bandgap reference circuit at different temperatures and processes according to the third embodiment of the present invention.

20‧‧‧Negative temperature coefficient voltage generator

200‧‧‧Operational Amplifier

M1~M4‧‧‧Gold Oxygen Semiconductor

VCC‧‧‧Power supply voltage

V _R4 ‧‧‧ voltage

R4‧‧‧ resistance

C‧‧‧ capacitor

Ictat’‧‧‧Negative temperature coefficient current

Claims (18)

A voltage generator includes: a first transistor, a first end coupled to a voltage source, and a second end coupled to a third end; a second transistor including a first end The second terminal is coupled to the third terminal. The first amplifier is coupled to the second end and the third end of the first transistor. The second input end is coupled to the second end and the third end of the second transistor, and an output end; a capacitor includes a first end coupled to the output end of the operational amplifier, and a first The second end is coupled to the ground end; a third transistor includes a first end coupled to the third end of the first transistor, and a second end coupled to the output end of the operational amplifier and the a first end of the capacitor, and a third end; a fourth transistor includes a first end coupled to the third end of the second transistor, and a second end coupled to the operational amplifier The output end is coupled to the first end of the capacitor, and a third end is coupled to the ground end; and a first resistor coupled to the The third transistor has three ends and between the ground terminal. The voltage generator of claim 1, wherein the first transistor and the second transistor are P-type MOS field effect transistors. The voltage generator of claim 1, wherein the operational amplifier has a P type An operational amplifier of a gold-oxygen half-field effect transistor and an N-type gold-oxygen half-field effect transistor. The voltage generator of claim 1, wherein the operational amplifier is configured to generate a control signal according to the signal received by the first input terminal and the second input terminal to control the operation of the third transistor. The primary critical region controls the fourth transistor to operate in a second critical region. The voltage generator of claim 1, wherein the third transistor and the fourth transistor are N-type MOS field-effect transistors. The voltage generator of claim 1, wherein the third transistor and the fourth transistor are different types of transistors, the threshold voltage of the third transistor is different from the threshold voltage of the fourth transistor, and The voltage difference between the two ends of the first resistor is equal to the voltage difference between the threshold voltage of the third transistor and the threshold voltage of the fourth transistor. The voltage generator of claim 1, wherein a voltage difference between the two ends of the first resistor is equal to a voltage difference between the gate source voltage of the third transistor and the gate source voltage of the fourth transistor. The voltage generator of claim 1, wherein the first resistor generates a negative temperature coefficient voltage according to a voltage difference between a gate source voltage of the third transistor and a gate source voltage of the fourth transistor, and according to The negative temperature coefficient voltage produces a negative temperature coefficient current. An energy bandgap reference circuit comprising: a positive temperature coefficient current source for generating a positive temperature coefficient current; and a negative temperature coefficient voltage generator comprising: a first transistor comprising a first end coupling The second transistor is coupled to the third terminal; the second transistor is coupled to the voltage source, and the second terminal is coupled to the third terminal; The operational amplifier includes a first input end coupled to the second end and the third end of the first transistor, and a second input end coupled to the second end of the second transistor and the second end a third end, and an output end; a capacitor comprising a first end coupled to the output end of the operational amplifier, and a second end coupled to a ground end; a third transistor comprising a first end The second end of the first transistor is coupled to the output end of the operational amplifier and the first end of the capacitor, and a third end; a fourth transistor, including a first end is coupled to the third end of the second transistor, and a second end is coupled to the operation The first end of the capacitor is coupled to the first end of the capacitor, and the third end is coupled to the ground end; and a first resistor is coupled to the third end of the third transistor and the ground end And generating a negative temperature coefficient voltage according to a voltage difference between a gate source voltage of the third transistor and a gate source voltage of the fourth transistor; a zero temperature coefficient voltage generator coupled between the positive temperature coefficient current source and the negative temperature coefficient voltage generator for generating a zero temperature coefficient voltage according to a positive temperature coefficient current and the negative temperature coefficient voltage . The energy band gap reference circuit of claim 9, wherein the first transistor and the second transistor are P-type MOS field effect transistors. The energy band gap reference circuit of claim 9, wherein the operational amplifier is an operational amplifier having a P-type MOS field effect transistor and an N-type MOS field effect transistor. The energy band gap reference circuit of claim 9, wherein the operational amplifier is configured to generate a control signal according to the signal received by the first input end and the second input end, to control the third transistor to operate in a The first critical region and the control of the fourth transistor operate in a second critical region. The energy band gap reference circuit of claim 9, wherein the third transistor and the fourth transistor are N-type MOS field effect transistors. The energy band gap reference circuit of claim 9, wherein the third transistor and the fourth transistor are different types of transistors, and the threshold voltage of the third transistor is different from the threshold voltage of the fourth transistor And a voltage difference between the two ends of the first resistor is equal to a threshold voltage of the third transistor and a threshold voltage of the fourth transistor difference. The energy band gap reference circuit of claim 9, wherein a voltage difference between the two ends of the first resistor is equal to a voltage difference between the gate source voltage of the third transistor and the gate source voltage of the fourth transistor . The energy band gap reference circuit of claim 9, wherein the first resistor generates a negative temperature coefficient current according to the negative temperature coefficient voltage. The energy band gap reference circuit of claim 9, wherein the zero temperature coefficient voltage generator comprises: a current mirror for replicating the negative temperature coefficient current; and a second resistor comprising a first end coupling And the third resistor includes a first end coupled to the second end of the second resistor and the positive temperature coefficient current source, and a second end coupled to the ground end; wherein The positive temperature coefficient current passes through the third resistor, the negative temperature coefficient current passes through the second resistor and the third resistor, and the zero temperature coefficient voltage is a voltage difference between the second resistor and the third resistor The sum of the voltage differences at both ends. The energy band gap reference circuit of claim 17, wherein the current mirror is a P-type MOS field effect transistor.