TWI361343B - Voltage reference circuit - Google Patents

Description

1361343 IX. Description of the Invention: [Technical Field] The present invention relates to a voltage reference source circuit 'and in particular to a CMOS voltage reference source circuit having low temperature dependence" [Prior Art] Voltage Reference Source ( Voltage Reference) circuits play an important role in many analog and mixed-signal circuits, such as oscillators, analog-to-digital (ADC), digital-to-digital analog (DAC), and phase-locked loops (PLLs). In general, the voltage reference source produces a stable voltage that does not vary with temperature, supply voltage, and Manufacture Drift as a reference voltage value in the circuit. Therefore, the main goal of the voltage reference source is to have good temperature stability (g〇〇d temperature stability), process stability, and stability to supply voltage changes, that is, independent of all external environmental factors. influences. At present, the most common is to use the Bandgap v〇ltage Reference circuit to compensate the negative temperature of the bipolar transistor (BJTs) base emitter (VBE) by a circuit proportional to absolute temperature (PTAT). Coefficient, but such a bandgap reference voltage circuit due to the base-emitter voltage of the Foxness coefficient is approximately linear and not really linear, so it cannot accurately eliminate the influence of the /-degree coefficient. The reference voltage affected by temperature requires compensation for higher order terms. In addition, the process of pure bipolar transistor (BJT) is relatively expensive. Therefore, generally 5 1361343 often uses a c臓 process (cheap process) to make a bipolar transistor, so it can only be realized by the parasitic effect of CMOS. The characteristics of the parasitic bipolar transistor that came out were inferior, and the circuit characteristics of the money composition were not good. The bipolar transistor crystallizer's base must be grounded during use, so that the range of the output voltage is limited.

In addition, the general-purpose bandgap reference circuit often uses a large resistive disk amplifier (QP Amp) and a high proportion of double-carrier transistors, which will cause an increase in area and error, and at the same time, a low supply voltage cannot be achieved. Low power consumption and low cost requirements. For the current portable electronic products, such as mobile phones, personal digital assistants (PDAs), notebook computers, etc., all of which are demanding light and short, the general energy gap reference ink circuit is no longer able to effectively extend the portable products. The use time of the battery makes it necessary to replace the battery or reduce the frequency of charging, so in recent years, the design of low-rise operation and low power consumption is more important. SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrical reference source circuit that does not use any one of a dipole (Di°des) and a bipolar transistor (BJTs) to overcome the above problems and provide — A reference voltage that is independent of the supply of electricity I and is not susceptible to temperature. In a preferred embodiment of the invention, a voltage reference source circuit includes a temperature-dependent voltage source (Temperature-stable Voltage), which is electrically connected to a one-dimensional current source (Widlar Current 6 1361343

Source )» The Ville source is used to supply a temperature-stabilized voltage reference source - a constant bias current independent of the supply voltage (Bias Current). The temperature-stabilized voltage reference source includes a first transistor, a second transistor, a third transistor, and a fourth transistor. The first transistor has a first source, a first drain, and a first a gate; a second transistor having a second source, a second drain, and a second gate; the third transistor 'having a third source, a third drain, and a third gate And the fourth transistor ' has a fourth source, a fourth drain, and a fourth gate. The first source and the second source are connected to a voltage source, the first gate is connected to the second gate and connected to an end point, the first drain is connected to the third drain, and the second drain is connected to the second drain. The third gate and the fourth source are connected to form a reference voltage terminal, the third source and the fourth gate are connected to a reference signal terminal, the fourth drain is connected to the reference signal terminal, and the Weiler current source includes a a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a resistor, the fifth transistor having a fifth source, a fifth drain, and a fifth gate; a sixth transistor having a sixth source, a sixth drain, and a sixth gate; the seventh transistor 'having a seventh source, a seventh drain, and a seventh gate; and The eight-electrode 'has an eighth source, an eighth drain, and an eighth gate. The fifth source is connected to the reference signal terminal, the fifth gate, the fifth drain and the sixth gate are connected, the sixth source is connected to one end of the resistor, and the other end of the resistor is connected to the reference signal. The seventh source is connected to the eighth source 7 1361343 to the power source, the seventh pole is connected to the fifth pole, the seventh closed pole, the eighth gate is the eighth 'and the pole and the sixth pole Connect to the endpoint.

According to another preferred embodiment of the present invention, a voltage reference source circuit includes: - a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth a crystal and a resistor, wherein the first transistor has a first source, a first drain, and a first gate; the second transistor has a second source, a second and a pole, and a first a second gate; the third transistor 'haves a third source, a third step, and a second gate, and the fourth transistor has a fourth source, a fourth drain, and a fourth gate The fifth transistor has a fifth source 'a fifth drain and a fifth gate; and a sixth transistor having a sixth source, a sixth drain and a sixth gate. The first source and the second gate are connected to a reference signal terminal, a first gate, a third gate, a fourth gate, a fifth gate, a sixth gate, a second source, and a fifth The drain pole is connected to form a reference voltage terminal, the second drain terminal is connected to the reference signal terminal, the first drain pole is connected to the fourth drain pole, the second drain pole is connected to the sixth drain pole, and the fourth source pole is The fifth source and the sixth source are connected to a voltage source, and the third source and one end of the resistor are electrically connected to the other end of the resistor to the reference signal terminal. According to the preferred embodiment of the present invention, the voltage reference source of the CM〇s transistor is used to provide different output voltages of the transistors by providing different bias voltages of the gates of the transistors, so that the circuit range of the application is large. And reduce the use of y electric aa body 3:, can reduce the cost and area, can also reduce the power consumption of the circuit" 1361343 [Embodiment] Generally, the "Complementary Metal-Oxide-Semi Conductor" (CMOS) The main parameters of temperature-dependent are mobility (m〇bili.ty) and threshold voltage (Threshold Voltage), so in CMOS circuits, the mobility and threshold voltage are the two main temperature sensitivities.

(temperature-sensitivity) factor. The temperature dependence of the threshold voltage (ντ) can be expressed as equation (1): VT{T) = VT(T 0) + a(T ~ T0) (1) where ' 7; =3 〇 0 ft, 〇: The temperature coefficient of the threshold voltage. The temperature dependence of the mobility (Μ) can be as shown in equation (2): KT) = ^〇(—)m (2) where m is the mobility rate temperature index, which is generally between -1.5~ depending on the process. Between -2

Please refer to FIG. 1 , which is a schematic diagram of a voltage reference source principle. The N-channel transistor (NM〇s) has a temperature dependence dependence on the threshold voltage of the p-channel transistor (pM〇s). With this characteristic, a temperature compensation circuit can be designed. The concept is similar to the voltage reference source principle shown in Figure 1. The threshold voltage of the p-channel transistor (PMOS) and the N-channel transistor (NM〇s) (,

Vtn) 110' 120 is adjusted by adjusting coefficients &, κ2, respectively, and their temperature coefficients can be canceled each other' to obtain a desired output reference voltage (Vref) 130. 9 1361343 %

Please refer to FIG. 2, which is a circuit diagram of a voltage reference source circuit according to a preferred embodiment of the present invention. The voltage reference source circuit includes a Widlar Current Source 200 and a Temperature-Stable Voltage Reference 300. The Ville source 200 is electrically connected to a temperature-stabilized voltage reference source 3, wherein the Q-Wuler current source 200 is used to supply a stable bias current (Bias Current) independent of the supply voltage. Reference source 3〇〇. The Weiler current source 200 includes four transistors (μ丨, M2, M3, M4) 211 to 214 and a resistor (R) 215. Each of the transistors 211 to 214 includes a source, a drain, and a gate, respectively. In this embodiment, the first and second transistors (Μ, M?〇, 2:1.1, 2丨2 are respectively N-channel transistors (NM0S). 'Second, 箄: potential zero': 曰5 Han (m3, m4) 213, 214 are P-channel transistors: (乂:

The first electric crystal, gas. ^|_ learning L1 source is connected to a reference signal end (such as · grounding, V〗 s: the gate is connected to the terminal and the second transistor (M2) .212 The gate is extremely electrically connected. The source of the second transistor (Μ) 2i2 is electrically connected to one end of the resistor (R) 215, and the other end of the resistor (8) 215 is connected to a reference signal terminal (eg, ground terminal or I The source of the third and fourth transistors (m3'M4) 213, 214 is connected to the - voltage source (vdd) 'the third transistor (the 汲 terminal of μ. 213 and the first transistor (M丨) 211) Extremely electrical connection. The third, fourth transistor ^3, the river 4) 213'214 gate extreme, the fourth transistor (team) 214 汲 extreme and the second transistor (m2) 212 汲 extreme connection Forming - Endpoint A. The third 'fourth transistor (%, 213, 214, 10 1361343 into a Current Mirror architecture, produces two currents of the same current value (I 丨, 12) 221, 222, which are mathematically The expression is as follows: /2 =-----L(1_ 丄μ^^Ψ/L) RlK 4I} (3) where Κ is the first transistor (Μ, ) 211 W/L and the second Crystal (M2) 212 W/L The ratio is negligible, and the gate width and length of each transistor are the oxide capacitance per unit area. a is the mobility of electrons. R is the resistance value of the resistor 215. It can be seen from the equation (3) that the current (h) 222 is independent of the supply voltage, and therefore, the Ville source current source circuit structure is a voltage reference source circuit that supplies a stable reference voltage. The & stable voltage reference source 3〇〇 contains four transistors (M^, M6, M7 'M8) 31 314. Each of the transistors 311 to 314 includes a source 'one bungee and one In the present embodiment, the fifth, sixth, and eighth transistors (PCT 5, ]\16, and River 8) 311, 312, and 314 are respectively 1 > channel transistor (PMOS) 'seventh transistor (Μ ?) 313 is an N-channel transistor (NMOS). The fifth and sixth transistors (m5, m6) 311, 312 are connected to a voltage source (Vdd), and their gate terminals are connected and connected to terminal A. It is used to receive the bias current (BiaSCurrent) e of the fifth transistor (M5) 311 which is independent of the supply voltage provided by the Villet current source 200. Connected to the 汲 terminal of the seventh transistor (Μ?) 313. The 汲 extreme of the sixth transistor (m6) 312, the gate terminal of the seventh transistor (Μ?) 313, and the eighth transistor (Ms) 314 The source terminals are connected to each other to form a reference voltage (Vref) terminal. The source terminal of the seventh transistor (M7) 313 and the eighth transistor (M8) 314 are connected to the reference signal terminal (eg, ground terminal or Vss). The eighth transistor (M8) 314 is connected to the reference signal terminal (such as ground terminal or Vss). In this embodiment, the gates of the seventh and eighth transistors (M7, M8) 313, 314 are It is in parallel with the source, so the gate-source voltage (VGS) is the same, which provides a temperature compensation mechanism for the threshold voltage and mobility to change with temperature. When the seventh and eighth transistors (M7, M8) 313, 314 operate in the saturation region, 'because of the same magnitude of bias current (Bias current)', therefore the seventh and eighth transistors (m7 'M8) 313, 314 The magnitude of the zeta current (1〇7, Ids) is also the same, as shown by equations (4) and (5): I〇7=~2 ^nC〇x~l^GS7 ~ Vtn^2 = \0 ^57 - vtn)2 (4) 1〇8 = j ^Pcoxj(yCS8 - = -2^(VCS8 - v^f (5) where ' and call p are the gain factors of the N-channel transistor and the p-channel transistor, respectively ( Gain factor. The gate-source voltage (VGS) of the seventh transistor (??) 313 is the same as the source-gate voltage (vSG) of the eighth transistor (Ms) 314, so let the seventh and eighth Transistor (, Ms) The immersion currents of 313, 314 are equal (Id7=Ids), and a reference voltage (Vref) can be obtained as shown in equation (6): 12 (6) 1136343

It can be seen from equation (6) that each variable is a function of temperature, in other words, the mobility dependency can be completely eliminated. The change of the voltage #voltage vTP is linear with the change of temperature, and the rate of 1^河〇3 and 1> River 〇3 is 〇13niV/t_2mVrc. This means that in the numerator of equation (4), the first term and the second term are inverse numbers (〇pp〇sitesign), that is, one is a positive sign and one is a negative sign, by appropriately selecting the formula in the temperature range ( The gain factor in 6) minimizes variations in temperature drift. . Referring to Figure 3, there is shown a circuit diagram of a voltage reference source circuit in accordance with another embodiment of the present invention. The voltage reference source circuit includes six transistors (Μ, M2, M3, M4 'M5, M6) 411 to 416' - a resistor (R) 417 and a capacitor 418. Each of the transistors 411 to 410 is separately packaged

It contains a source, a drain and a gate. In this embodiment, the first and second transistors (Μ!, Μ3) 411, 413 are respectively Ν channel transistors (NMOS) 'second, fourth, fifth, sixth transistors (μ2, μ4, Μ5'Μ6) 412, 414, 415, 416 are ρ channel transistors (pm〇s), respectively. The source terminal of the first transistor (Μ, ) 411 is connected to the gate terminal of the second transistor (m2) 412 to a reference signal terminal (eg, ground terminal or Vss), first, third, fourth, 5. The sixth transistor (Μ丨, M3, M4, M5, M6) 411, 413, 414, 415, 416 gate terminal, the second transistor (m2) 412 source terminal and the fifth transistor (m5) 413 is extremely connected to form a reference voltage (VREF) terminal. The second transistor (m2) 412 is connected to a reference signal terminal (such as ground terminal or vss). The first transistor (the 汲 terminal of 411 is connected to the 汲 terminal of the fourth transistor (m4) 414. The 汲 terminal of the third transistor (M3) 413 is connected to the 汲 terminal of the sixth transistor (M6) 416. The fourth, fifth, sixth transistor (m4, M5, M6) 414, 415, 416 source terminal is connected to a voltage source (vdd). The third transistor (Ms) 413 source terminal and resistor (r One end of the resistor 417 is electrically connected, and the other end of the resistor (R) 417 is connected to a reference signal terminal (such as ground terminal or Vss). One of the capacitors 418 is terminated to the reference voltage (vREF) terminal, and the other end thereof is connected to a reference signal terminal (eg, ground terminal or %〇. In this embodiment, the first, third, fourth, and sixth transistors (Μι, Μ3, Μ4, Μδ) 411, 413, 414, 416 and the resistor The (R) 417 constitutes a Widlar Current Source circuit structure, and the first, first, fourth, and fifth transistors 415 and the capacitor 418 form a temperature-stabilized voltage reference circuit. Architecture, where Villeer current (4) is used to supply a temperature-stable electrical reference source - independent of The steady-state bias current (Bias Current) should be the same. According to equations (1), (4) and (6), the Viller motor source circuit architecture provides a current independent of the supply voltage (U, the first The crystal (Ml) 411 and the second transistor (M2) 412 are connected back-to-back in parallel, so that the source and the closing voltage (VSG) are the same in size, so that all the currents are the same 'to balance the fluctuation caused by the temperature, and then Provides - a stable reference to the supply voltage and temperature-independent 14 1361343 (Vref). Refer to Figure 4, which is a simulation of the voltage reference source circuit shown in Figure 3. Figure 4 Simulation curve of temperature change versus output voltage at different process boundaries (pr〇cess Corners). Process boundaries include TT (Typical-Typical Model) 410, FF (Fast-Fast Model) 420, SS (Slow-Slow Model) 430 In this embodiment, the supply voltage of the voltage reference source circuit is 0.9V, and the quiescent current can generate an average reference voltage of about 557mV. Please refer to FIG. 5a and FIG. 5b, which are shown as the voltage reference source of FIG. Circuit The simulation curve. Figure 5a is the simulation curve of the temperature change to the output voltage at different process corners in the case of the maximum supply voltage (ι.4ν). The process boundary contains ττ (Typical-Typical Model) 511 'FF (Fast-Fast Model) 521 ^ SS (Slow-Slow Model) 53l. The external plot is a simulated curve of temperature change versus output voltage at different process corners in the case of a minimum supply voltage (0.7). The process boundary includes ττ (Typical-Typical Model) 512, FF (Fast-Fast Model) 522, SS (Slow-Slow Model) 532 ® temperature variation range from -70 ° C to 15 (the variation of the output voltage between TC) Is ±115"V or (Χδρρπι/Ι. As the supply voltage is from 0.7V to 1.4V, its maximum temperature coefficient is only 2 25ppm/〇c. Although the invention has been disclosed above by several preferred embodiments, it is not The present invention is intended to be limited to the scope of the present invention, and the scope of the invention is as described in the appended claims. The above description of the above and other objects, features, advantages and embodiments of the present invention will be more clearly understood. The detailed description of the drawings is as follows: Figure 1 is a 2 is a circuit diagram of a voltage reference source circuit according to a preferred embodiment of the present invention. FIG. 3 is a diagram showing another preferred embodiment of the present invention. Electric dust reference source circuit Fig. 4 is a simulation diagram of the voltage reference source circuit of Fig. 3. Fig. 5a and Fig. 5b are diagrams showing the simulation of the voltage reference source circuit of Fig. 3, respectively. DESCRIPTION OF SYMBOLS] 110: threshold voltage 120: threshold voltage 111: coefficient 121 · coefficient 130: output reference voltage 200: Weiler current source 211 to 214: transistor 215: resistors 221 to 222: currents 311 to 314: transistor 300 : Temperature Stabilized Voltage Reference Sources 411 to 416: Transistor 417: Resistor 418: Capacitor 41CT: Process Boundary 420: Process Boundary 1613343 430: Process Boundary 511 to 512: Process Boundaries 521 to 522: Process Boundaries 531 to 532: Process boundary

17

Claims (1)

1361343 __ December 30, 100 revised replacement page X. Patent application scope: i. A voltage reference source circuit, including: A temperature-stabilized voltage reference source comprising four transistors, each being a first transistor, a second transistor, a third transistor, and a fourth transistor, the first transistor having a -first source a first source, a second source, a second source, a second gate, and a second gate; the third transistor has a third source a third drain and a third gate; and the fourth transistor has a fourth source, a fourth drain, and a fourth gate; and a Weiler current source electrically connected to the temperature One end of the voltage reference source for providing a bias current independent of the supply voltage, so that the temperature stable voltage reference source is not affected by the supply voltage variation; wherein the first source is connected to the second source To a voltage source, the first gate is connected to the second gate and connected to the end, the first drain is connected to the third drain, the second drain, the third gate And the fourth source is connected to form a reference voltage terminal, and the third source is connected to the fourth terminal End of a reference signal, the fourth drain terminal connected to the reference signal. 2. The voltage reference source circuit of claim 1, wherein the Villes current source comprises: a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a a resistor, the fifth transistor has a fifth source, a fifth drain, and a fifth gate; the sixth transistor has a sixth source, a sixth drain, and a sixth gate The 18th 1361343 __December 30th, the replacement page seven transistor has a seventh source, a seventh drain and a seventh gate, and the eighth transistor has an eighth source An eighth drain and an eighth gate; wherein the fifth source is connected to the reference signal terminal, the fifth gate, the fifth drain, and the sixth gate are connected, the sixth source The pole is connected to the terminal, the other end of the resistor is connected to the reference signal terminal, the seventh source and the eighth source are connected to the voltage source, and the seventh drain and the fifth The pole phase is connected, (four) seven, the π pole, the eighth pole and the sixth pole are connected to the end point. 3. The voltage reference source circuit of claim 2, wherein the third transistor, the fifth transistor, and the sixth transistor are (four) transistors, the first transistor, the second transistor What is the crystal, the fourth transistor, the seventh transistor, and the eighth transistor? Channel Electron Crystal (PMOS)〇 A voltage reference source circuit comprising: a crystal, a first temperature-stabilized voltage reference source, comprising a first solar day, a fourth transistor, and a fifth transistor; a third transistor; a sixth transistor; and a resistor; 1361343 And a second gate; the third transistor has a third source, a third drain, and a third gate; the fourth transistor has a fourth source, a fourth drain, and a a fourth gate; the fifth transistor has a fifth source, a fifth drain, and a fifth gate; and the sixth transistor has a sixth source, a sixth drain, and - a sixth gate; the first source and the second gate are connected to a reference signal terminal, the first gate, the third gate, the fourth gate, the fifth gate, and the sixth The gate, the second source, and the fifth and the poles are connected to form a reference voltage: the second terminal is connected to the reference signal terminal, and the first drain is connected to the fourth drain. The third drain is connected to the sixth drain, the fourth source, the fifth source and the a source are connected to a voltage source, and the third source is electrically connected to one end of the resistor The other end of the resistor is connected to the reference signal terminal. 5. The voltage reference source circuit as described in claim 4 of the patent application The temperature-stabilized voltage reference source further includes a capacitor, one end of the capacitor is connected to the reference voltage terminal, and the other end of the capacitor is connected to the reference signal terminal. 6. The voltage reference source circuit of claim 5, wherein the first transistor, the third transistor, the fourth transistor, the sixth transistor, and the resistor form a Weiler And a current source, wherein the Ville source is used to supply the temperature-stabilized voltage reference source to a stable bias current independent of the supply voltage. The voltage reference source circuit of claim 6, wherein the first transistor and the third transistor are N-channel transistors (NMOS); the second transistor, the fourth battery The crystal, the fifth transistor, and the sixth transistor are P-channel transistors (PMOS). XI, schema Z, such as the next page Correction replacement page on December 30, 100