TW200832099A - Bandgap reference circuit - Google Patents

Abstract

A bandgap reference circuit comprises: a reference current generation circuit for generating first and second reference currents on first and second current paths; a current mirror, generating a third reference current on a third current path based on the first and second reference currents; an operation amplifier for making the first reference current substantially equal to the second reference current; and a feedback circuit, for making a node voltage on the first current path substantially equal to another node voltage on the third current path, for eliminating possible errors caused by channel length modulation effect in the current mirror.

Description

200832099 P2006-004-TW-B 21217twf.doc/n IX. Description of the invention: [Technical field of the invention] The present invention is an improved method of the _gap reference circuit, which can improve the energy gap reference electrical power supply repulsion (PSRR) and the electricity of the number of money. [Prior Art] "Digital analog converters (DACs), analog-to-digital converters (ADCs) or regulators require at least one fixed and stable reference voltage. 2. This reference voltage is best used each time the power is turned on. It can be stably regenerated. The reference voltage of the phase is preferably not affected by process variation, operating temperature variation, and g source variation. The bandgap reference circuit can be used to provide the voltage of the test. Therefore, in many In electronic systems, the bandgap reference circuit plays an important role because it determines the overall stability and accuracy of the system. In general, the bandgap reference circuit will include several main parts: electricity /; 丨 l mirror operation amplification State, bandgap current generator and load. Figure 1 shows the circuit diagram of the conventional bandgap reference circuit. This bandgap reference circuit includes: MOS transistor Mil~M13; operational amplifier 〇pl; BJT transistor Qii And (312, resistors R11 and R12 (which form the bandgap current generator); and resistor R13. The gap current generator of Figure 1 contains two current paths: IIA and I1B, I1A = I1B = I 11+I12.111 is the positive temperature coefficient (PTAT) current, and m is the negative temperature coefficient (CTAT) current. Therefore, ideally, I1A/I1B synthesized by I11+I12 can be regarded as temperature independent. In addition, since the operation of the current mirror, I1C>I1A=I1B, lie can also be regarded as temperature-independent current. Because Vref=i1C*r13, Vref can also be It is regarded as a temperature-independent voltage. However, when considering the channel length modulation effect of the MOS transistor, I1A-IIB^IIC. This is because the virtual ground effect (VIA^VIB) through the operational amplifier makes the M〇s transistor M11 and M12 have the same drain-source voltage. However, the other node voltage Vlc is not necessarily equal to V1A/Vm. As a result, the drain-source voltages of the MOS transistors Mil and VQ2 are not necessarily equal to the MOS transistor M13. The drain-source voltage; that is, VDSM11=VDSM1#VDSM13. The mismatch of this drain_source voltage is equivalent to the power supply and temperature, that is, the material does not (4) the repulsion and the temperature coefficient. It is better to have an improved technique of the energy gap reference circuit, which can improve, know, and shortcomings of the surgery. Poor temperature coefficient and pSRR characteristics. In addition, = is good, can be achieved without special circuit components, that is, can be realized in the standard CMOS process. [Invention] Therefore, the present invention provides an improvement of the energy gap reference circuit. Architecture, which can be used for general current-mode (gap) reference circuits. Further, the present invention provides a preferred Winlin-based PSRR of a bandgap reference circuit. ^Reading it can (4) The present invention further provides a circuit that can be used in the low-relationship of the low-relationship/(10) flap, the road d: 目 =; 明 proposed - the kind of energy can be used in the first and 200832099 P2006- 004-TW-B 21217twf.doc/n a second current path 経 first and second reference current; a current mirror, according to the first and second reference currents to generate a second dream current on the third current path ; - the first operational amplifier, pure to the second current path of the first disk - the first node voltage is dedicated to the second node voltage on the second current path; a feedback = the first And a third current path such that the first node U is dedicated to the third node voltage on the second current path; and the - Mai Khao load, touching the shout circuit to provide a reference invention The above and other objects and features of the present invention are described below with reference to the preferred embodiments of the present invention. [Embodiment] In the present MOSA example, in order to improve the voltage mismatch of the 亟 亟 亟 为 为 为 为 为 为 为 MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS MOS The sewing machine is finely pressed against each other. The circuit of the 源 源 源 降低 降低 降低 降低 降低 降低 降低 降低 降低 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道 通道Refer to the second, ί road block diagram. The energy gap reference circuit includes: a current mirror 210, a 哉 哉 哉 1 " 〇Ρ 2 施 gap current generator 22G, and a feedback circuit 230 兴 R2. The sag current generator 220 is used to generate temperature independent current I2A and 200832099 P2006-004-TW-B 21217twf.doc/n I2B. Here, the structure of the band gap current generator 22() may not be particularly limited, and at least this function can be achieved. Operating the amplifier 〇p;21 allows the node voltage V2A = V2B. The current mirror 21G mirrors another temperature-independent current I2C according to the current generated by the band gap current generator 220, I2A and I2B. Similarly, in the case of Λ, the structure of the current mirror 210 is not particularly limited, and i can achieve this function. The feedback circuit 230 can cause the node circuit V2C = V2A, so that all of the MOS transistors (not shown) in the current mirror 21 can have substantially the same drain-source voltage. Thus, even if the channel length modulation effect is considered, the currents generated by all of the M?s transistors in the current mirror 210 substantially match each other. That is, assuming that the MOS transistors for generating the current I2A, I2B and I2C are the same size, then I2a = I2b = I2c, and the currents I2A, I2B and I2C are temperature independent. The feedback circuit 230 includes, for example, an operational amplifier 22 and a transistor M21. The positive and negative inputs of the operational amplifier 〇P22 are respectively coupled to the node φ point V2A and the node V2C, and the output end thereof is coupled to the gate of the M〇s transistor M21. The source of the MOS transistor M21 is coupled to the node V2c and the current mirror 210', and its gate is connected to the output of the operational amplifier 〇p22, and its drain is coupled to the load R2. 3 to 6 show several examples of the present embodiment, and those skilled in the art will recognize that the present invention is not limited to the examples. The bandgap reference circuit of FIG. 3 includes: MOS transistors M31 to M33 (which constitute a current mirror); an operational amplification state OP31; an operational amplifier 〇p32 and an MOS transistor M34 (which constitutes a feedback circuit); and a plurality of current elements ( For example, BJT transistor Q31 and 8 200832099 P2006-004-TW-B 21217twf.doc/n Q32, resistors R31 and R32; and resistor R33. In addition, the current component can be used in addition to the BJT transistor. The body, the gold-oxide semi-transistor operating in the sub-critical region or the diode-connected N-channel MOSFET (diode turn-on NMOS), etc. The negative feedback effect through the operational amplifiers OP31 and OP32 , making V3A-V3B=V3C. As a result, MOS transistors M31~M33 are not

The pole-source voltages are substantially equal to each other. Even if the channel length modulation effect is considered, the current I3A/I3B/I3C generated by the M0S transistors M31 to M33 will be equal to each other (assuming that the sizes of the M0S transistors M31 to M33 are equal). The energy gap reference circuit of Figure 4 includes: PCT (10) transistor] ^ 41 ~ from 43 (which constitutes the current mirror); operating amplifier 〇 P4i; M0S transistor M44 and operational amplifier OP42 (which constitutes the feedback circuit); Components (such as BJT transistor Q41/Q42; resistor R41/R42; and load R43. In addition, the current component can be used in addition to BJT transistor: diode, gold oxide and semi-electricity operating in the subcritical region. The crystal or diode is connected to the N-channel MOS transistor, etc. The bandgap reference circuit of Figure 5 includes: M〇s transistor composed of current mirror); operational amplifier 0P51; M〇s transistor M55 And operation • Amplified state 52 P52 (which constitutes the feedback circuit); several current components (such as BJT transistor Q51~Q53); resistors R51~R55; and load R56. Further, the current element may be implemented by a BjT transistor, a diode, a MOS transistor operating in a subcritical region, or a diode-connected N-channel ytterbium semi-transistor. The energy gap circuit of Fig. 6 includes: MOS transistor M61~M63 (the 9 200832099 P2006-004-TW-B 21217twf.doc/n constitutes a current mirror); an operational amplifier OP61; a MOS transistor M64 and an operational amplifier OP62 ( It constitutes a feedback circuit); several current components (such as MOS transistors M65 to M66, which operate in the subcritical region); resistors... R61 to R63; and load R64. Further, the current element can be implemented by using a MOS transistor operating in a subcritical region, or a diode, a BJT transistor, or a diode-connected n-channel MOS transistor. '

For the sake of brevity, the detailed operation principle of FIG. 4 to FIG. 6 will not be repeated here, but it is known to those skilled in the art that the structure of FIG. 4 to FIG. 6 and the principle of FIG. 2 can be known to avoid the channel length modulation effect. The resulting error. To further demonstrate the advantages that can be produced by this embodiment, the inventors have enumerated several simulated characteristic graphs in Figures 7 to 1A. 7a and 7b are graphs showing the relationship between the reference voltage VREF and the temperature of the prior art (Fig. 3) and the present embodiment (Fig. 3). In the graph % and graph %, the five curves represent the relationship between the different voltage sources (VDD gas 0V, VDD Tubu = 12V, Chat 3 and VDD4.4V) from top to bottom. Note that since the reference voltages obtained at various voltage sources are very similar in this embodiment, it is not easy to distinguish five curves in Fig. 7b. , w, the knowing technology (Fig. 1) and the present embodiment (Fig. 3) under different voltage sources

10 200832099 P2006-004-TW-B 21217twf.doc/n Figures 8a to 8f show the relationship between the reference voltage VREF and the temperature of the prior art (Fig. i) and this embodiment (Fig. 3) under different voltage sources. Figure. In Figure 8a to Figure 8f, the symbol PFNF stands for pM〇s Fast Radisson 8

Fast, while PTNT stands for PMOS Typical NMOS Typical and PSNS stands for PMOS Slow NMOS Slow. The meaning of PFNF and PTNT fish PSNS. is known to those skilled in the art and will not be described in detail herein. Similarly, in Figures 8a to 8f, the five curves represent the relationship between different voltage sources (VDD = 1.0V, VDD = 1.1, • VDD = 1·3 and VDD = 1.4V) from top to bottom. . Note that since the reference voltages obtained by the various voltage sources are very close in this embodiment, it is not easy to distinguish five curves in Figs. 8d to 8f. Figures 9a and 9b are graphs showing the relationship between the reference voltage VREF and the voltage source of the prior art (Figure 1) and this embodiment (Figure 3). In Figure % and Figure 9b, the five curves represent the relationship between the top and bottom curves at different simulated temperatures (-40^, 〇〇C, +25〇c, +85 and +125.〇). Since the reference voltages obtained by different voltage sources are very similar in this embodiment, it is not easy to distinguish 5 curves in Fig. 9b. A comparison of the jSRR coefficients of the prior art (Fig. 1) and the present embodiment (Fig. 3) at different temperatures is as follows. ------K __L Temperature (cc) -40 -- 0 -- +25 +85 PSRR (%/y) Conventional Technology (Fig. 1) 12.44 8.19 6.81 4.63 3.44 —----- This embodiment (Fig. 3) 0.06 0.09 0.19 0.22 0.26 11 200832099 P2006-004-TW-B 21217twf.doc/n Figure 10a to Fig. 10 shows the conventional technology (Fig. 1) and Benbe _ (Fig. 3) at different simulated temperatures. The reference voltage VR£F vs. electricity (four) relationship diagram. Similarly, in the figure, the five curves represent the relationship between the top and bottom curves at different simulated temperatures (_4〇〇c, 〇〇c, +25〇c, +85〇c盥+125^Q). Please note that in this embodiment, the reference made at various nuclear temperatures is close to the light, so it is not easy to distinguish five curves in the graphs 〇d~i〇f. The advantage of the embodiment is that it can provide better temperature coefficient and SRR characteristics, and can be operated in low-spinning operation with low charm. In addition, because another operational amplifier is used to make the MOSFET of all MOS transistors in the current mirror The source voltages are substantially equal to each other, and thus the circuit error due to the channel length modulation effect can be reduced. Although the present invention has been disclosed in the preferred embodiments as above, it is not intended to limit the invention, and anyone skilled in the art, In the spirit and scope of the invention, the scope of protection of the present invention is subject to the definition of the scope of the appended patent application. [Simplified illustration] # Figure 1 shows Circuit diagram of a conventional bandgap reference circuit. A circuit block diagram of a bandgap reference circuit in accordance with a preferred embodiment of the present invention. / Figures 3 to 6 show several examples of embodiments of the present invention. Figures 7a and 7b show a conventional technique (Fig. 7 and Figure 7) Figure 3) A plot of the reference voltage VREF versus temperature. 12 200832099 P2006-004-TW-B 21217twf.doc/n Figures 8a to 8f show the conventional techniques under different voltage sources (this is called this embodiment ( ® takes the reference voltage VREF vs. temperature graph., ® 9a and Figure 9b show the relationship between the reference voltage VREF of the prior art (Fig. 1) and the present embodiment (Fig. 3) versus the ink source. a ~ Figure 10f shows the relationship between the reference voltage VREF and the voltage source of the conventional technique (Fig. 1) and the Benbe example (Fig. 3) at different simulated temperatures. [Main component symbol description] φ M11 ~ M13 , M21, JVI31 ~ M34, M41 ~ M44, M51 ~ M55, M61 ~ M66: MOS transistor OP1, OP21, OP22, OP31, OP32, OP41, OP42, OP51, OP52, OP6 BU OP62: Operational amplifier Q1 Bu Q12, Q3 Bu Q32, Q4 Bu Q42, Q51 ~ Q53 : BJT Electric Touching Japanese Body

Rl 1 to R13, R2, R31 to R33, R41 to R43, R51 to R56, R61 to R64: resistance 210: current mirror • 220: band gap current generator 230: feedback circuit 13

Claims (1)

200832099 P2006-004-TW-B 21217twf.doc/n X. Application for Patent Park: 1. A bandgap reference circuit comprising: - a reference current generating circuit for generating a first reference current in the -first current path; a current mirror, based on the first reference current to generate a second reference current on the second current path; and a feedback bypass coupled to the first and second current paths to cause the first current path The voltage at point H above is essentially equal to one of the second node voltages on the second Φ current path. ^如中#专利|& The bandgap reference circuit described in item 1 further includes a McCaw load that is touched to provide a reference voltage. 3. The pot generating circuit described in item # patent of the patent # is generated on the third electric fine - the third measuring current. ^ For example, the energy gap reference circuit described in the third paragraph of the patent | & surrounding the third item, for the Ail, has: - the positive input end, secret to the first diameter; a negative input end - engage to the The first current path is connected to the current mirror by - and an output terminal. 5·”Please refer to (4) The feedback circuit described in item 2 includes: - the second operational amplifier and the reference circuit of the fourth operation described in item 5 of the 4th patent today, wherein the device has: - a positive input The terminal is coupled to the second electrical current path, and coupled to the second current path, and coupled to the first transistor. 7. As described in claim 6 Bandgap reference circuit, wherein: 200832099 P2006-004-TW-B 212I7twf.doc/n the first transistor has: - a source, the second current path, a gate, coupled to the second operational amplifier The wheel current output terminal is coupled to the reference load by a diode. The current reference circuit of the energy gap reference according to claim 1 includes: /, at least one first a current component coupled to the first current path, 1 capable of conducting current on the first current path; and The second current component is coupled to the second current path, and the current is conducted on the second current path, wherein each of the first current component and the second current component can be: The junction transistor, the diode, the gold oxide semi-transistor operating in the subcritical region or the diode-connected N-channel MOS transistor is selected. 9. A bandgap reference circuit comprising: /current path-reference current generating circuit, respectively generating a first and a second reference current on a first and a first; a current mirror 'according to the first and second A third reference current is generated on the reference current-current path; the spear-/one-operating amplifier' is lightly connected to the first and second current paths, and the second-stage voltage is substantially equal to 5 One of the second node voltages on the path of the two brothers; and the operational amplifier of the first two and third currents are electrically connected to the first current and the third current path. The electrical history is essentially equal to the first current path of the first one = the second of its 15 200832099 F2UU6-U〇4-TW-B 21217twf.doc/n Two current paths; a negative input terminal coupled to the first current path, and an output terminal coupled to the current mirror. The gap amplifier reference circuit of claim 9, wherein the second operational amplifier has a positive input coupled to the second current path, and a negative input coupled to the third Current path, and an output. 12·If the energy gap reference circuit mentioned in item n of the patent application scope, The first transistor has a first source coupled to the third current path, a gate coupled to the output of the second operational amplifier, and a gate. 13. The bandgap reference circuit of claim 12, further comprising a reference load coupled to the drain of the first transistor. 14. The gap current reference circuit of claim 9, wherein the reference current generating circuit comprises: , , and a first current component coupled to the first current path, wherein Conducting a current on a turbulent path; and - a second current component coupled to the second current path, the current being conducted on the = two current path, the second current element and the second current The components can be selected from: J曰2 surface transistors, diodes, gold oxide half-days operating in the subcritical region, or N-channel MOS transistors. b·—the energy gap reference circuit, including: the upper generation of the electricity generation, the in-first-and-second current path-the soil-reference current; the electric mirror, according to the first-and second reference current The third power 16 200832099 F20U6-U〇4-TW-B 21217twf.doc/n generates a third reference current in the flow path; a first operational amplifier coupled to the first and second current paths 'to One of the first node voltages on the first current path is substantially equal to one of the second node voltages on the second current path; a feedback circuit coupled to the first and third current paths to cause the first node The voltage is substantially equal to one of the third node voltages on the third current path; and a tea test load coupled to the feedback circuit to provide a reference power Pressure. 16) The energy gap reference circuit of claim 15, wherein the first operational amplifier has a positive input terminal coupled to the second current path, and a negative input terminal coupled to the first The current path, as well as an output terminal, is connected to the current mirror. 17. The bandgap reference circuit of claim 15, wherein the feedback circuit comprises a second operational amplifier and a first transistor. 18. The gap reference circuit of claim 17, wherein the 2: ί operational amplifier has: - a positive input terminal, _ to the first package flow path technology; and a H end 'from the first to the third The current path, as well as the output, is connected to the first transistor. ^9. The energy gap reference circuit of claim 18, wherein the two S'1 crystals have: a source, a secret to the third current path: = as the output of the amplifier; and - 17 200832099 rzuuo-u04-TW-B 21217twf.doc/n at least a first current component coupled to the first current path, the current can be conducted on the first current path; and the at least one second current The component is coupled to the first electrode to conduct current on the second current path, and the pen grasping path, wherein each of the first current element and the second redundant crystal, the diode, and the second half (4) The connection mode of the body or the diode is selected in the channel MOS semi-transistor