TWI380154B - Bandgap reference circuits - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a bandgap reference circuit, and more particularly to a bandgap reference circuit for high voltage and low quiescent current. [Prior Art] Electronic circuits, such as analog-to-digital converters, linear or switching voltage regulators, etc., usually require the use of a reference voltage for voltage ‘also referred to as bandgap voltage. The hoisting operation, in which the reference voltage is a stable voltage that is not affected by temperature and supply voltage changes. As a general matter, the bandgap reference circuit is a common reference circuit which provides reference power independent of temperature and supply voltage. Figure 1 shows a conventional bandgap reference circuit 100. Energy gap reference

The base of crystal Q3 is related to the emitter voltage (v (Vbe). In Figure 1, the electricity

~ Tian ~ a month analog circuit needs a stable majority of the high voltage analog circuit's gap voltage capacity

Bandgap voltage. However, VISS004/0516-A41825twf 4 affects the supply voltage. Therefore, it is required to provide a high-capacity reference circuit for high-voltage u and low-quiescent current for high-voltage analog circuits. [Invention] For providing a gap reference circuit, including: - input node, supply voltage; - an output node for providing a - reference voltage; a first transistor, lightly connected to the gate of the above-mentioned human point, η junction, and the output node, having a first control terminal; Between the node and the above-mentioned (four) end; - the first control terminal has a second point; - the third transistor has a - third control terminal - a partial pressure = day = and A f is also amplified according to the first voltage and the upper differential, and a signal is sent to the third control terminal. 1, the pressure difference is provided again. 'The present invention provides another type of energy gap reference circuit, which is used to receive a supply voltage; 0 is a reference voltage; a first electric day, ^ is a point, with Providing a round out node, having a ::: pole node and the above-mentioned ingress node and the above-mentioned first-electrode crystal 1, pure to the above-mentioned wheel polarity junction transistor, coupled between two; a first NPN type double base Very close to the closed end of the output node body, having - NPN type bipolar junction electric - 'B day body, lightly connected to the above-mentioned first pole; one voltage dividing unit, according to the above one ground end 'has a closed A second voltage, ·, and - differential test. The voltage provides a first (four) and VISS004 / 〇 516-A41825twf device according to the above first

a voltage difference between C 1380154 and the second voltage provides a signal to the gate of the second transistor, wherein the first transistor and the second transistor are N-type MOS semiconductor worms, and The breakdown voltage of the first transistor is higher than the breakdown voltage of the second transistor. The above and other objects, features and advantages of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt;

Embodiments: Bipolar-Complementary Metal Oxide Semiconductor (CMOS) - Double diffused metal oxide semiconductor (Double diffused metal Oxide) for power application components

The Semiconductor, DMOS process, also referred to as the BCD process, is a widely used semiconductor process. By using the BCD process, a low-voltage MOS transistor, a high-voltage MOS transistor, and a bipolar junction transistor (bip〇larjuncti〇n transistor) can be simultaneously provided in one circuit/element. BJT) (NPN type and pNp type are available). One of the advantages of the BCD process is the ability to use high voltage components. In addition, good component matching characteristics can be achieved by the NPN type bipolar junction transistor provided by the BCD process to reduce the offset at the input of the differential amplifier. Figure 2 is a block diagram showing a bandgap reference circuit 200 not according to an embodiment of the invention. The bandgap reference circuit 200 can receive the supply voltage VCC' from the input node Nin and provide the reference voltage VREF at the output point Nout. The bandgap reference circuit 200 includes transistors μ1, M2 and Q1, resistors ri, VISS004/0516-Α41825twf 6 1380154 ··

The differential amplifier 210 and the voltage dividing unit 220. The voltage dividing unit 220 includes three resistors R2, R3, and R4 and a transistor Q2. In this embodiment, the electromorph M1 and the transistor M2 are N-type MOS transistors. Further, the transistor Q1 is an NPN type bipolar junction transistor, and the transistor Q2 is a PNP type bipolar junction transistor. In the band gap reference circuit 200, the transistor M1 is coupled between the input node Nin and the output node Nout. The resistor R1 is coupled between the input node Nin and the gate of the transistor M1. The transistor Q1 is coupled between the gate of the transistor M1 and the transistor M2, wherein the base of the transistor Q1 is coupled to the output node Ν_. The transistor M2 is coupled between the transistor Q1 and the ground GND, wherein the gate of the transistor M2 is coupled to the output of the differential amplifier 210. In the voltage dividing unit 220, the resistor R2 is coupled between the output node Ν_ and the resistor R3, and the resistor R4 is coupled between the resistor R3 and the transistor Q2, wherein the base of the transistor Q2 is coupled to Ground GND. Referring to Fig. 2, when a current flows through the voltage dividing unit 220, the voltage dividing unit 220 generates a reference voltage VREF, a voltage VI, and a voltage V2. In addition, the voltage across the resistor R3 (ie, the voltage difference between the voltage VI and the voltage V2) can be amplified by the differential amplifier 210 to generate a signal AMPOUT to control the transistor M2, thereby changing the current flowing through the transistor M2. the size of. Due to the change in current on transistor M2, the voltage across resistor R1 also changes. The change in the voltage across the resistor R1 adjusts the gate-to-source voltage of the transistor M1, and then the current flowing through the transistor M1 also changes, and finally the reference voltage VREF is regulated to the desired voltage value. It is worth noting that the breakdown voltage of the transistor M1 is higher than the breakdown voltage of the transistor M2 and the transistor in the differential amplifier 210. In addition, although the supply voltage VISS004/0516-A41825twf 7 1380154 VCC will change from the low voltage level to the high voltage level, the transistor Q1 can protect the transistor M2 by stabilizing the drain-to-source voltage of the transistor M2. . Figure 3 is a block diagram showing a bandgap reference circuit 300 in accordance with another embodiment of the present invention. The bandgap reference circuit 300 can receive the supply voltage VCC from the input node Nin and provide the reference voltage VREF at the output node Nout. The bandgap reference circuit 300 includes transistors M1, M2 and Q1, a resistor IU, a differential amplifier 310, a voltage dividing unit 320, and a starting circuit 330. The differential amplifier 310 includes transistors M5-M8 and Q3-Q6 and resistors R7-R9, wherein the transistor M5 and the transistor M6 are P-type MOS transistors, and the transistor M7 and the transistor M8 are N-type gold oxides. The semiconductor transistor, and the transistor Q3-Q6 are NPN type bipolar junction transistors. As described earlier, the voltage dividing unit 320 includes three resistors R2, R3, and R4 and a transistor Q2. The start-up circuit 330 includes resistors R5 and R6 and transistors M3 and M4, wherein the transistor M3 and the transistor M4 are N-type MOS transistors. It is worth noting that the breakdown voltage of the transistor M1 is higher than that of the transistor M2 and the breakdown voltage of the transistor in the differential amplifier 310 and the startup circuit 330. Furthermore, the capacitor C1 is coupled between the gate of the transistor M2 and the output node Nout. Capacitor C1 is used as a compensation to confirm that the bandgap reference circuit 300 is in a stable state. In the start circuit 330, the resistor R6 is coupled between the resistor R5 and the transistor M4. The gate of the transistor M4 is coupled between the resistor R5 and the resistor R6. The transistor M3 is coupled between the gate of the transistor M2 and the ground GND. The gate of the transistor M3 is coupled between the resistor R6 and the transistor M4. In the differential amplifier 310, the resistors R7, R8, VISS004/0516-A41825twf 8 9 are respectively transferred to the output node Nout. The f crystal MM is lightly connected between the pull-up VI and the transistor (10), wherein the gate of the transistor M6 is lightly connected to the i-side GND. The transistor M5 is coupled to the resistor R7 and the transistor [/], and the gate of the medium-voltage body M5 is connected to the ground terminal gnd. The external Q-system Q6 is connected between the resistor R9卩 and the ground GND, and the electric body Q5 is coupled between the ground GND and a node, wherein the seven nodes are located in the transistor q3 and the electricity. Between crystals Q4. The transistor, Q3 柘 is coupled between the node and the resistor, wherein the base of the transistor q3 is between the resistor R3* and the resistor R4, and is used to receive the voltage v2. The body Q4 is coupled between the node and the resistor R7. The base of the transistor Q4 is consumed between the resistor R2 and the resistor R3 and is used to receive the voltage VI. Referring to Figure 3, first, when the supply voltage vcc starts to climb from 〇v, all signals in the bandgap reference circuit are at a low voltage level. Then, the gate of the transistor M1 changes with the supply voltage vcc, so the gate-to-source voltage of the transistor M1 increases. When the supply voltage beast increases, the current flowing through the transistor M1 will also start to increase, and the above current will be supplied to the bandgap reference circuit 3〇〇 and coupled to the transistor.

Inside the branch circuit of Ml. Then, when the above current flows through the voltage dividing unit 32, the reference voltage VREF starts to rise. * The voltages π and V2 are also generated. Therefore, the voltage across the resistor R3 (i.e., the voltage difference between the voltage νι and the voltage V2) will increase by 'and be proportional to the rise above the reference voltage vref. Next, the voltage across the resistor R3 changes the difference in current between the differential amplifier 31 and the current between the transistors Q4 and Q3. In the differential amplifier 31〇, VISS004/0516-A41825twf Λ 1380154 transistor Q3 is N times larger than the transistor Q4 to form the base-to-emitter voltage difference ΔνΒΕ, which is the base-to-emitter of the transistor Q4. The voltage and the voltage difference between the base and emitter voltages of transistor Q3, wherein the current flowing through the transistor is greater than the current flowing through transistor Q4. When the voltage across the resistor r3 is less than the base-to-emitter voltage difference Δλ/βΕ, the base-to-emitter voltage difference can be obtained according to the following formula (1): AVBE=V, x\nN (工)

Where Vt is a thermal voltage. Since the current flowing through the transistor q3 is greater than the current flowing through the transistor Q4 and the resistor R7 and the resistor R8 have the same resistance value, the voltage across the resistor R8 will be greater than the cross-over at the resistor R7. Therefore, the current flowing through the transistor M6 will be less than the current flowing through the transistor, and then the transistor M8 will pull down the gate of the transistor M2 to turn off the transistor M2. When no current flows through the transistor M2, the transistor Q1, and the resistor R1, the gate of the transistor Μ1 continues to increase with the supply voltage vcc. Then 'the reference voltage VREF will increase with the supply voltage vcc until the voltage across the resistor R3 is slightly larger than the base-to-emitter voltage difference ΔVbe ° when the voltage across the resistor R3 is slightly larger than the base-to-electrode difference. The current flowing through the transistor Q4 becomes larger than the current flowing through the transistor q3. Then, the voltage across the resistor R7 will be greater than the voltage across the resistor R8. Therefore, the current flowing through the transistor M6 will be larger than the current flowing through the transistor M5, and then the transistor M6 will pull up the gate of the transistor M2. Next, for transistor M2, the increase in gate-to-source voltage will result in more current, and the voltage across resistor R1 will also increase. The increase in the voltage across the resistor R1 means that the transistor M1 has a stable gate-to-source voltage, and its VISS004/0516-A41825twf 10 1380154 will stabilize the current flowing through the transistor M1. When the current flowing through the transistor 1 does not increase for a long time, the reference voltage VREF can be obtained according to the following formula (2): vREF = vBEQ2+[3^yVxhiN (7) where VBEQ2 is the base-to-emitter of the transistor Q2. Voltage. The base-to-emitter voltage VBEQ2 has a negative temperature coefficient, and the multiple of the thermal voltage Vt has a positive temperature

coefficient. Therefore, the sum of the parameters in equation (2) can cause the bandgap reference circuit 300 to be unaffected by temperature and supply voltage. In the startup state, when the reference voltage VREF is smaller than the base-to-emitter voltage of the conventionally turned-on bipolar junction transistor, the base of the transistor Q5 is caused by the collector-to-emitter voltage of the transistor being a low voltage. The current will be very small. The base current of transistor Q5 is the same as the current flowing through transistor q6 and resistor R9. Furthermore, since the transistor q5 is operated in the saturation region, the collector current of the transistor Q5 will be smaller than the collector current of the transistor q6. Similarly, the collector-to-emitter voltage of transistor Q3 and transistor Q4 is also low voltage' so that both transistor Q3 and transistor Q4 operate in the saturation region. At this time, since the differential amplifier 310 is inoperative, there is no current difference between the transistor q3 and the transistor q4, so the gate of the transistor M2 will be set to an arbitrary value. Since the problem of noise or component mismatch may exist in the bandgap reference circuit 300, the voltage on the gate of the transistor M2 may be pulled high enough to introduce current into the transistor M2. Therefore, the voltage across the resistor ri increases, and the current flowing through the transistor M1 decreases. Thus, the reference voltage VREF will stop increasing and stay below the desired voltage value. When the reference voltage VREF is lower than the base-to-emitter voltage of the conventionally turned-on bipolar junction transistor VISS004/0516-A41825twf 1380154 body, the start-up circuit 33〇 pulls down the gate of the transistor M2 to ensure that the current still flows. Via transistor Ml. The voltage on the gate of the transistor M1 by turning off the transistor M2 will be equal to the supply voltage VCC' so that current can be supplied to all branches of the bandgap reference circuit 300. When the reference voltage VREF reaches the base-to-emitter voltage of a conventionally turned-on bipolar junction transistor, the differential amplifier 31 will begin to operate and the transistor M3 will be turned off. Since the differential amplifier 31〇 starts to work,

The reference voltage VREF is stabilized to the voltage value obtained by the above formula (2). As previously described, for a BCD process, the bandgap reference circuit is a stable circuit. In addition, the bandgap reference circuit provides high voltage and low quiescent current. Furthermore, the bandgap reference circuit can achieve low reference voltage variations and low quiescent current over a wide range of supply voltages. The present invention has been disclosed in the above preferred embodiments, but it is not intended to be used by those skilled in the art, and it is possible to make a few changes and refinements without departing from the spirit and scope of the present invention. : The scope of protection is defined as the “simplified description of the figure” defined by the scope of the patent application attached. Figure 1 shows a conventional bandgap reference circuit;

2 is a block diagram showing an energy path according to the present invention - an embodiment; and a band gap reference described in the embodiment of the present invention. FIG. 3 is a block diagram showing another practical circuit according to the present invention. [Main component symbol description] 100, 200, 300 ~ band gap reference circuit; 210, 310 ~ differential amplifier; VISS004/0516-A41825twf 12 1380154 220, 320 ~ voltage dividing unit; 330 ~ start circuit; AMP OUT ~ signal; C1~capacitor; GND~ground; M1-M8, Q1-Q6~ transistor; Nin~ input node; N-~ output node;

R1-R9~ resistance; VCC~ supply voltage; and VREF~ reference voltage. VISS004/0516-A41825twf 13

Claims (1)

1380154 VII. Patent application scope: 1. A bandgap reference circuit comprising: an input node for receiving a supply voltage; an output node for providing a reference voltage; and a first transistor coupled to the input The node and the output node have a first control end; a first resistor coupled between the input node and the first control end; a second transistor coupled to the first control terminal, having a second control terminal coupled to the output node; a third transistor coupled between the second transistor and a ground terminal, a third control terminal; a voltage dividing unit, providing a first voltage and a second voltage according to the reference voltage; and a differential amplifier providing a voltage difference between the first voltage and the second voltage The signal is to the third control terminal. 2. The gap reference circuit of claim 1, wherein the first transistor and the third transistor are N-type MOS transistors, and the breakdown voltage of the first transistor is higher than The breakdown voltage of the above third transistor. 3. The gap reference circuit of claim 1, wherein the second transistor is an NPN type bipolar junction transistor. 4. The bandgap reference circuit of claim 1, wherein the voltage dividing unit comprises: a second resistor coupled to the output node; VISS004/0516-A41825twf 14 1380154 a third resistor coupled The second resistor is coupled to the third resistor; and a PNP-type bipolar junction transistor is coupled between the fourth resistor and the ground, and has a base coupling And the voltage difference between the first voltage and the second voltage is a voltage across the third resistor. 5. The gap reference circuit of claim 1, further comprising a capacitor coupled between the output node and the third control terminal. 6. The gap reference circuit of claim 1, further comprising: a start-up circuit coupled between the output node and the third control terminal. 7. The bandgap reference circuit of claim 6, wherein the starter circuit comprises: a fourth transistor coupled between the third control terminal and the ground terminal, and having a fourth control terminal a fifth resistor coupled to the output node; a sixth resistor coupled between the fifth resistor and the fourth control terminal; and a fifth transistor coupled to the fourth control terminal and A fifth control terminal is coupled between the grounding terminal and the fifth resistor and the sixth resistor. 8. The gap reference circuit of claim 1, wherein the differential amplifier comprises: a seventh resistor, an eighth resistor, and a ninth resistor respectively coupled to VISS004/0516-A41825twf 15 1380154 An output node; and a MOS transistor, wherein the seventh resistor has a gate coupled to the ground; and: λ: a P-type MOS transistor connected to the eighth resistor and Between the second control terminals, having a closed-pole light connection to the grounding end; - an -N-type MOS transistor coupled to the first p-type MOS transistor and the ground In the above-mentioned first-P type MOS semiconductor crystal crystal = having a first N-type MOS transistor and the grounding end being lightly connected to the third control I (four) thin, having a pole reduction a gate of a MOS transistor; a sigma-dipolar junction (10), between the nodes, having a base for receiving the second voltage and a second Wei interface transistor Receiving a base for receiving the first voltage as described above; One end of the ground has a base lightly coupled to the == point: and the fourth bipolar junction transistor is coupled between the ninth resistor and the ground end, and has a base coupled to the ninth resistance. 9. The bandgap reference circuit of claim 8, wherein the first, second, third and fourth bipolar junction transistors are nPN type bipolar junction transistors. 10. The energy gap reference circuit of claim 8 wherein said first bipolar junction crystal system is larger than said second bipolar junction transistor, such that said first bipolar junction transistor There is a voltage difference between the base-to-emitter voltage VISS004/0516-A41825twf 16 1380154 and the base-to-emitter voltage of the second bipolar junction transistor described above. 11. A bandgap reference circuit comprising: an input node for receiving a supply voltage; an output node for providing a reference voltage; a first transistor coupled between the input node and the output node a first resistor coupled between the input node and the gate of the first transistor; a first 双-type bipolar junction transistor coupled to the first transistor a gate having a base coupled to the output node; a second transistor coupled between the first 双-type bipolar junction transistor and a ground terminal, having a gate; a voltage dividing unit Providing a first voltage and a second voltage according to the reference voltage; and a differential amplifier, providing a signal to the second transistor according to a voltage difference between the first voltage and the second voltage*· a gate, wherein the first transistor and the second transistor are Ν-type MOS transistors, and the breakdown voltage of the first transistor is higher than the second The body of the collapse voltage. 12. The bandgap reference circuit of claim 11, wherein the voltage dividing unit comprises: a second resistor coupled to the output node; a third resistor coupled to the second resistor; a fourth resistor coupled to the third resistor; and a VISS004/0516-Α41825twf 17 1380154 PNP type bipolar junction transistor, coupled between the fourth resistor and the ground terminal, having a base coupled to The grounding end, wherein the voltage difference between the first voltage and the second voltage is a voltage across the third resistor. 13. The gap reference circuit of claim n, further comprising a capacitor coupled between the turn-off node and the gate of the first transistor. 14. The bandgap reference circuit of claim 5 further comprising a start-up circuit coupled between the output node and the gate of the second transistor. 15. The bandgap reference circuit of claim 14, wherein the starter circuit comprises: a third transistor coupled between the gate of the second transistor and the ground terminal, having a gate pole; a fifth resistor coupled to the output node; a sixth resistor coupled between the fifth resistor and the gate of the third lightning body; and a fourth transistor coupled to the third A gate of the transistor and the grounding end have a gate coupled between the fifth resistor and the sixth resistor. 16. The bandgap reference circuit of claim 15, wherein the first transistor has a breakdown voltage higher than a breakdown voltage of the third transistor and the fourth transistor. 17. The gap reference circuit of claim 5, wherein the VISS004/0516-A41825twf 1380154 differential amplifier comprises: a seventh resistor, an eighth resistor - the output node; and the $9 resistor are respectively connected The utility model has a gate light and a fifth transistor, and is connected to the seventh resistor to be connected to the grounding end; the body is lightly connected to the eighth resistor and the second electrical body: a pole: 1 having - ask very lightly connected to the above grounding terminal; a gate of the end, and a gate between the ancient five-day solar body and the grounding is lightly connected to the fifth transistor; - the second mountain transistor is lightly connected to the gate of the second transistor and Between the above grounds, there is a P 极 pole - 笛 - say W complement the gate of the transistor; the first - NPNi bipolar junction transistor, _ resistance and between a node, with - base (four) to receive The second voltage second NPN is connected to the crystal, and is called between the first resistor and the node to have a base for receiving the first voltage; a fourth NPN type bipolar junction transistor, (4) Between the node and the grounding end, a base is coupled to the ninth resistor; and a fifth NPN-type bipolar junction transistor is lightly connected between the ninth resistor and the grounding end, and has a The base is coupled to the ninth resistor. 18. The gap reference circuit of claim 17, wherein: the fifth transistor and the sixth transistor are p-type MOS transistors, and the seventh transistor and the above The eight transistor is a &gt; type MOS transistor. 19. The gap reference circuit of claim 17, wherein VISS004/0516-A41825twf 1380154 is configured to be larger than the third NPN type bipolar junction transistor described above, such that There is a difference between the base-to-electrode voltage of the second NPN-type bipolar junction transistor and the base-to-emitter voltage of the third NPN-type bipolar junction transistor. 20. The bandgap reference circuit of claim 17, wherein the first transistor has a breakdown voltage that is higher than a breakdown voltage of the fifth, sixth, seventh, and eighth transistors. VISS004/0516-A41825twf 20