TW201039090A - Bandgap reference circuits - Google Patents

Abstract

A bandgap reference circuit is provided. An input node receives a supply voltage. An output node provides a reference voltage. A first transistor is coupled between the input node and the output node and has a first control terminal. A resistor is coupled between the input node and the first control terminal. A second transistor is coupled to the first control terminal and has a second control terminal coupled to the output node. A third transistor is coupled between the second transistor and a ground terminal and has a third control terminal. A voltage dividing unit provides a first voltage and a second voltage according to the reference voltage. A differential amplifier provides a signal to the third control terminal according to a difference between the first and second voltages.

Description

201039090 VI. Description of the Invention: [Technical Field] The present 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 a reference voltage for normal operation. The reference voltage is not affected by temperature and supply voltage variations. A stable voltage. In general, the bandgap reference circuit is a common reference circuit that provides a reference voltage independent of temperature and supply voltage, also known as bandgap voltage. Figure 1 shows a conventional bandgap reference circuit. The bandgap reference circuit 100 uses a feedback loop mode to establish an operating point such that the output voltage VREF can be generated by the first voltage and the second voltage. Wherein, the voltage system is related to a multiple of the base-to-emitter voltage difference UVBE of the transistor pair and Q2 operating at different current densities, and the second voltage system is opposite to the base-to-emitter voltage of the electro-optical crystal Q3 ( Vbe) related. In the figure i, the electrodes Ql, Q2 and Q3 are NPN type bipolar junction transistors (BJT). Further, the first voltage AVbe is proportional to the absolute temperature (PTAT) and thus has a positive temperature coefficient, and the second voltage vBE has a negative temperature coefficient. Therefore, the sum of KAVbe (k is a multiple) and the base-to-emitter voltage VBE produces a voltage that is almost independent of temperature and supply voltage. In general, s, for proper performance, the analog circuit requires a stable bandgap voltage. However, the voltage gap voltage of most high voltage analog circuits is VISS004/0516-A41825twf . 201039090 is susceptible to temperature and supply voltage. Therefore, there is a need for a bandgap reference circuit that provides high voltage and low quiescent current for use in high voltage analog circuits. SUMMARY OF THE INVENTION The present invention provides 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 node And a first control terminal between the output node and the point; a first resistor coupled between the input node and the first control terminal; and a second transistor coupled to the first a control terminal having a second control terminal coupled to the output node; a third transistor coupled between the second transistor and a ground terminal, having a third control terminal; a voltage dividing unit, And providing a first voltage and a second voltage according to the reference voltage; and a differential amplifier providing a signal to the third control terminal according to a voltage difference between the first voltage and the second voltage. Furthermore, the present invention provides another energy gap reference circuit comprising: an input node for receiving a supply voltage; an output node for providing a 'reference voltage; a first transistor coupled to The input node and the output node have a gate; a first resistor coupled between the input node and the gate of the first transistor; a first NPN-type bipolar junction transistor a gate coupled to the first transistor, having a base coupled to the output node; a second transistor coupled between the first NPN-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, according to the first voltage, VISS004/0516-A41825twf 5 201039090 and the above a voltage difference between the second voltages provides a signal to the gate of the second transistor, wherein the first transistor and the second transistor are N-type MOS transistors, and the above Day day crash electrical system voltage is higher than the body of the breakdown voltage of the second transistor. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; Example: For a power application component, a Bipolar CMOS-Complementary Metal Oxide Semiconductor (CMOS) Double Diffusion Metal Oxide Semiconductor (DMOS) process, also referred to as a BCD process, 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 (BJT) can be simultaneously provided in one circuit/element ( NPN type and PNP type are available). One of the advantages of the BCD process is the availability of high voltage components. In addition, the NPN-type bipolar junction transistor provided by the BCD process can achieve good component matching characteristics to reduce the offset at the input of the differential amplifier. Figure 2 is a block diagram showing a bandgap reference circuit 200 in accordance with an embodiment of the present 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 node Nm. The bandgap reference circuit 200 includes transistors M1, M2 and Q1, a resistor R1, a VISS004/0516-A41825twf 6 201039090 differential amplifier 210, and a voltage dividing unit 220. The sub-relationship _ a ^ no - η ^ I half 疋 220 includes three resistors R2, phantom and R4, and the transistor Q2 body (4) and the transistor Μ 2 are Ν-type MOS transistors. The crystal Q1 is a ΝΡΝ-type bipolar junction transistor, and the transistor is a ΡΝΡ-type bipolar junction transistor from &amp; Α 遐 and the transistor Q2. Reference gap in the energy gap

In the 峪200, the transistor M1 is coupled between the input node Nin and the output node N iN〇ut. Thunder P and R1 will be coupled between the input node Nin and the gate of the transistor]Vfl &amp; '. Transistor

The Q1 is coupled between the gate of the transistor M1 and the lightning contact λ ^ between the input and the solar body M2. The base of the transistor Q1 in the basin is coupled to the output node Ν connected to the transistor Q1 and the ground GND. Between the Ganzi±between the gate of the transistor M2 is coupled to the differential amplifier 210 for her turn. In the voltage dividing unit 220, the resistor R2 is coupled between the output node N〇m and the resistor phantom, and the resistor R4 is coupled between the resistor R3 and the transistor Q2, and the base of the transistor Q2 is coupled. Connect to ground GND. /' 90 Reference Fig. 2 When the current flows through the voltage dividing unit 22, the voltage dividing unit 220 generates the reference voltage VREF, the voltage vi, and the 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 the signal ampout to control the transistor M2' to thereby change the current flowing through the transistor M2. the size of. Due to the change in current on transistor M2, the voltage across the resistor Ri will also change. 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 that of the transistor M2 and the breakdown voltage of the transistor in the dynamic amplifier 210. In addition, although the supply voltage VISS004/0516-A41825twf 7 201039090 vcc will change from the low voltage level to the high power M level, by stabilizing the drain voltage of the transistor M2 to the source voltage, the transistor Q1 can be used Japanese body] M2 is available for protection. 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 wheel-in node and provide the reference voltage VREF at the output node Nout. The bandgap reference circuit 300 includes transistors [VH], M2, and Qi, an electric resistance R-differential amplifier 310, a voltage dividing unit 320, and a starting circuit 33A.差 The differential amplifier 310 includes transistors Μ5-Μ8 and Q3-Q6 and resistors R7-R9, wherein the transistor Μ5 and the transistor Μ6 are Ρ-type MOS transistors, and the transistor Μ7 and the transistor Μ8 are Ν-type The MOS transistor 'and the transistor Q3-Q6 are ΝΡΝ-type bipolar junction transistors. As described earlier, the voltage dividing unit 320 includes three resistors R_2, R3, and R4 and a transistor Q2. The start-up circuit 330 includes resistors R5 and R6 and transistors M3 and Μ4, wherein the transistor M3 and the transistor Μ4 are Ν-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 33. 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 so that the green bandgap reference circuit 300 is in a steady 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 connected between the gate and the transistor M4. In the differential amplifier 31〇, the resistors R7, R8 VISS004/0516-A41825twf 8 201039090 and the R9 are assigned to the wheel node Ν_. The transistor _ is connected between the light resistor R8 and the transistor Μ8, wherein the gate of the transistor Μ6 is coupled to the ground GND. The transistor Μ5 series is connected to the resistor R7j^ transistor M7. The gate of the zhongzhong electric body μ5 is switched to the ground terminal gnd. In addition, the transistor Q 6 is (four) between the resistor R 9 卩 and the ground terminal (10) D, and the transistor Q5 is consumed between the ground terminal and a node, wherein the node is located in the transistor Q3 and the transistor Q4. between. The transistor Q3 Ο ◎ is connected between the above node and the resistor R8, wherein the base of the transistor Q3 is connected between the resistor R3 and the resistor R4 and is used to receive the voltage v2. The electric body Q 4 _ is connected between the above node and the resistor R7, wherein the base of the electromorph Q4 is connected between the resistor R2 and the resistor illusion and is used to receive the voltage VI. Referring to the 3 ® 'first' when the supply voltage VCC starts to rise from the GV, all signals in the bandgap reference circuit 300 are at a low voltage level. Then, the gate of the transistor M1 changes with the supply voltage vcc because the gate-to-source voltage of the transistor M1 increases. When the supply voltage vcc • ◎ is increased, the current flowing through the transistor M1 will also start to increase, and the above current will be supplied to the band gap reference circuit 3 to be coupled to all the branch circuits of the transistor M1. Then, when the above current flows through the voltage dividing unit 320, the reference voltage VREF starts to climb and the voltages V1 and V2 are also generated. Therefore, the voltage across resistor R3 (i.e., the voltage difference between voltage V1 and voltage V2) will increase and is proportional to the rise above reference voltage VREF. Then, 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 „ 201039090 : 1Q3 is N times larger than the Q4 of the galvanic crystal Q to form the base-to-pole E, which is the base-to-emitter of the transistor Q4. Voltage and voltage difference between the base-to-emitter voltage of transistor Q3, wherein the current flowing through the transistor is greater than the current flowing through transistor Q4. When the voltage across resistor R3 is less than the base-to-emitter When the voltage difference is suppressed, the base-to-emitter voltage difference Δ and pulsation can be obtained according to the following formula (1): hVBE=Vtx\nN ( 1 )

〇〇 where Vt is the thermal voltage. Since the current flowing through transistor q3 is greater than the current flowing through transistor Q4 and resistor R7 and resistor R8 have the same resistance value, the voltage across resistor R8 will be greater than the voltage across resistor R7. Therefore, the current flowing through the transistor M6 will be less than the current flowing through the transistor M5' 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 M1 continues to increase with the supply voltage VCC. Then, the reference voltage VREF increases with the supply voltage VCC until the voltage across the resistor R3 is slightly larger than the base-to-emitter voltage difference ΔVbe 0 when the voltage across the resistor R3 is slightly larger than the base-to-emitter voltage difference AVbe' 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 greater 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 voltage across resistor R1 means that transistor M1 has a stable gate-to-source voltage, which is VISS004/0516-A41825twf 10 201039090. When flowing through transistor M1 VREF, it can flow through the transistor according to the following] The current becomes stable. When the current does not increase for a long time, the reference voltage is calculated by the equation (2): vREF=vBEQ2+[^yVtXlnN (2) where VBEQ2 is the base-to-emitter voltage of the transistor Q2. The base-to-emitter voltage Vqing has a negative temperature coefficient' and the multiple of the thermal voltage has a positive temperature

coefficient. Therefore, the sum of the parameters of equation (7) can make the bandgap reference circuit 300 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, since the collector-to-emitter voltage of the transistor q5 is at a low voltage, the transistor Q5 is The 0 pole current will be very small. The base current of transistor Q5 is the same as the current flowing through the transistor and resistor R9. Furthermore, since transistor Q5 is operating in the saturation region, the collector current of transistor Q5 will be less than the collector current of transistor Q6. Similarly, the collector-to-emitter voltages of transistor Q3 and transistor Q4 are also voltages, so 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 that 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 will increase and the current flowing through the transistor M1 will decrease. 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-conducting bipolar junction transistor VISS004/0516-A41825twf 11 201039090 body, the startup circuit 330 pulls down the gate of the transistor Μ2 to ensure that the current still flows. Via transistor Ml. By turning the transistor Μ2 off, the voltage on the gate of the transistor M1 is equal to the supply voltage VCC' and thus supplies current to all branches of the bandgap reference circuit 3''. When the reference voltage VREF reaches the base-to-emitter voltage of the conventionally turned-on bipolar junction transistor, the differential amplifier 31 will start operating and the transistor M3 will be turned off. Since the differential amplifier 31 〇 starts operating, the reference voltage VREF is stabilized to the voltage value obtained by the above formula (2).

〇 Ο As described earlier, for the BCD process, the bandgap reference circuit is a stable circuit. In addition, the bandgap reference circuit provides high voltage and low static motors. 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. However, it is not intended to be construed as limiting the scope of the invention. The scope of the invention is defined by the scope of the patent application. 1 is a conventional energy gap reference circuit. FIG. 2 is a block diagram showing a real circuit according to the present invention; and the energy gap reference described in the embodiment.

Energy Gap Reference as described in the embodiment Fig. 3 is a block diagram showing another circuit in accordance with the present invention. [Major component symbol description] 100, 200, 300 ~ bandgap reference circuit; 210, 310~ differential amplifier; VISS004/G516·Α41825twf 12 201039090 220, 320~ voltage divider unit; 330~ start circuit; AMP OUT~ signal; C1~capacitor; GND~ground;

M1-M8, Q1-Q6~ transistor; Nin~ input node; N〇ut~ output node; R1-R9~ resistor; VCC~ supply voltage; and VREF~ reference voltage.

VISS004/0516-A41825twf 13

Claims (1)

201039090 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 gap reference circuit of claim 1, wherein the voltage dividing unit comprises: a second resistor coupled to the output node; VISS004/0516-A41825twf 14 201039090 a second resistor, coupled Connected to the second resistor; a fourth resistor coupled to the third resistor; and a PNP-type bipolar junction transistor, having a base coupling between the fourth resistor and the ground terminal And the voltage difference between the first power source 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 circuit coupled to the output node and the third control terminal. I. 7. The energy gap reference circuit of claim 6, wherein the starting circuit comprises: ~ a fourth transistor coupled between the third control terminal and the ground terminal, having a fourth control 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 the 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 201039090 The output node, has a 3:==::-the first increase, and the ## semi-conductive hard m handle is connected to the eighth resistor - the first =: = a closed pole is coupled to the ground end; the MOS semiconductor The electric 曰 21 electric 曰 body is coupled to the first P type 〇Ο 上 上 上 上 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : a gate of the MOS transistor is coupled to the first N-type node (the double-connected 3-connector transistor, coupled to the eighth resistor and the first to receive the second voltage; Between the nodes, the ::: body is coupled to the seventh resistor and the third bipolar: the surface is used to receive the first voltage; between the ground, 4 L: lightly connected to the node and In the above, a base is coupled to the ninth resistor; and the 匕, sink Hill bipolar junction transistor 'coupled between said ninth resistor and, l ^' having a base connected to the ninth light resistance. Said, the application of the application, the bandgap reference circuit of the eighth item, wherein the upper bipolar junction is 曰^: and the fourth bipolar junction transistor is the coffee type. The gap reference circuit, wherein the second-th polarity junction electro-crystal system is larger than the second bipolar-connected crystal 'the base-to-emitter voltage of the first bipolar junction transistor is VISS004/0516-A41825twf 丨丄Electricity! 201039090 There is a voltage difference between 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 NPN-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 NPN-type bipolar junction transistor and a ground terminal, having a gate; a unit, providing a first voltage and a second voltage according to the reference voltage; and q-differential amplifier, providing a signal to the second transistor according to a voltage difference between the first voltage and the second voltage 〇 a gate, wherein the first transistor and the second transistor are N-type gold oxide semiconductor transistors, and the breakdown voltage of the first transistor is higher than the second The breakdown voltage of the crystal. The energy gap 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; The fourth resistor is coupled to the third resistor; and the VISS004/0516-A41825twf 17 201039090 PNP type bipolar junction transistor is coupled between the fourth resistor and the ground end, and has a base coupled to the base The grounding end, wherein the lightning lag between the first voltage and the second voltage is a cross-grinding of the third resistor. The energy gap reference circuit as described in claim 5, wherein a valley is coupled between the output node and the second transistor 匕. The gate electrode includes a bandgap reference circuit as described in claim 11, and further includes a start-up circuit coupled between the output node and the gate of the first body. 15. The energy gap reference circuit of claim 14, wherein the starting circuit comprises: ', a third transistor, and a gate coupled to the second transistor to be between the ground terminals Having a gate; a fifth resistor coupled to the output node; a sixth resistor coupled between the fifth resistor and the gate of the third body; and C-Crystal The fourth transistor is coupled between the gate of the third transistor and the ground, and has a gate coupled between the fifth resistor and the sixth resistor. The above-mentioned 16. The energy gap reference circuit of claim 15, wherein the breakdown voltage of the first transistor is higher than the breakdown voltage of the fourth transistor by the fourth transistor. And 17. The energy gap reference circuit according to the scope of claim 5, the complex VISS004/0516-A41825twf /, 201039090, the differential amplifier comprises: a seventh resistor, a x x rain output node; / resistor And the ninth resistor is connected to a fifth transistor 'transferred to the grounding end; the third seven resistors have a gate light and a sixth transistor, which is lightly picked up at the 曰舻 η The eighth resistor and the closed pole of the second electric solar cell are connected to the ground end; the seventh transistor is coupled to the gate of the D terminal, and the fifth transistor is described in the past. And the grounding is between 4 and the gate is coupled to the fifth transistor; an eighth transistor is coupled between the gate of the second transistor and the grounding end, and has an explanation #阄阄 and upper] poles are coupled to the seventh transistor, the second type of bipolar pull, and the s±upper resistance and -to w are coupled to the eighth resistor and - the point between the 'has- The base is used to receive a third type of bipolar junction transistor, which is lightly connected Between the first Ϊ resistor and the node, there is a base for receiving the first galvanic bipolar junction transistor, and _ has a base coupling between the section _ ^ way ground &amp; Connected to the ninth resistor; a fifth (four) type bipolar junction transistor coupled between the ninth lightning resistance and the ground terminal, having a base _ connected to the ninth resistor as claimed in the patent application The energy gap reference circuit described in item 17 is the fifth transistor and the sixth transistor described above. A type of gold oxide crystal, and the seventh transistor and the eighth electric semiconductor transistor described above.勹以尘金虱 19. The energy gap as described in claim 17 of the scope of the VISS004/0516-A41825twf electric tower 'where ° 10 201039090 the above second NPN type bipolar junction electro-crystal system is larger than the third NPN The bipolar junction transistor has a voltage 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 The difference exists. 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