Bias current source with wide voltage range

Abstract

The invention provides a bias current source with a wide voltage range. The bias current source comprises a bias current generation module and a bias current output module. The bias current generation module generates the bias current, the bias current changes little within the power supply voltage range of 5.5 V-52V, the self-starting function is achieved, the bias current generation module is prevented from being in the zero state, the tubes M1-M4 form a cascode structure, the influence of VDD change on the output bias current can be reduced, and the output bias current is stable. The capacitor C1 and the capacitor C2 can reduce the influence of the jitter of the voltage VDD on the bias current, and the anti-interference performance is high; the bias current output module can provide pull bias current and sink bias current according to needs, and the bias current generation module and the bias current output module are matched with each other, so that the bias current is small in change along with temperature, and the precision is high.

Description

Technical Field

[0001] The invention relates to the field of electrical technology, and in particular to a bias current source with a wide voltage range. Background Art

[0002] In order to work stably, high-performance analog integrated circuits and mixed analog and digital circuits require bias current sources with small temperature changes, high stability, self-start, and wide input voltage range. Bias current sources are an important reference source in analog integrated circuits and mixed analog and digital integrated circuits, providing bias current to other modules in the chip. The bias current should change little with changes in power supply voltage and temperature.

[0003] However, the conventional resistor divider bias current source circuit is Figure 1 As shown, either the power consumption is large or the layout area is large, and the bias current varies greatly with temperature and the input power supply voltage varies greatly, and the input voltage range is small. Summary of the invention

[0004] The present invention is to solve the problem that the bias current varies greatly with temperature and input power supply voltage, and provides a bias current source with a wide voltage range, including a bias current generating module and a bias current output module. In the present invention, the bias current generating module generates a bias current, and the bias current varies very little within the power supply voltage range of 5.5V to 52V, and also has a self-starting function to prevent the bias current generating module from being in a zero state. The M1 to M4 tubes form a common source and common gate structure to reduce the influence of the change of VDD on the output bias current, and the capacitors C1 and C2 can reduce the influence of the voltage VDD jitter on the bias current, and have strong anti-interference performance; the bias current output module of the present invention can provide a bias current pull and a bias current injection as needed, and the bias current generating module and the bias current output module cooperate with each other to make the bias current vary little with temperature and have high precision.

[0005] The present invention provides a bias current source with a wide voltage range, comprising a bias current generating module and a bias current output module connected;

[0006] The bias current generating module outputs a positive temperature coefficient bias current to the bias current output module. The bias current output module cooperates with the bias current generating module to output a source current P27_G and a sink current C13_PLUS and reduce the influence of temperature on the output current.

[0007] The bias current generating module includes tubes M1 and M2 whose sources are respectively connected to the power supply voltage VDD, a tube M3 whose source is connected to the drain of the tube M1, a tube M4 whose source is connected to the drain of the tube M2, a tube M10 whose drain is connected to the drain of the tube M3, a resistor R1 and a resistor R2 connected in parallel with the source of the tube M10, a tube Q1 whose collector is connected to the other end of the resistor R1 and whose base is connected to the other end of the resistor R2, a resistor R4 connected to the emitter of the tube Q1, a resistor R3 whose one end is connected to the drain of the tube M4, a collector connected to the other end of the resistor R3 and whose emitter is connected to the resistor R4 and is grounded. a tube Q2 connected to the end thereof, a Zener diode Q3 connected to the gate of the tube M10 with its negative electrode, a resistor R6 connected to the power supply voltage VDD at one end thereof, a tube M11 connected to the drain at the other end thereof and to the gate at the negative electrode of the Zener diode Q3, tubes M5 and M6 connected to the source at the tube M11 respectively, a capacitor C2 connected in parallel with the tube M6, a resistor R8 connected to the drain at one end thereof, a tube Q4 connected to the collector at the other end thereof, a resistor R9 connected to the drain at one end thereof, and a tube M7 connected to the gate and the drain at the other end thereof;

[0008] The gate and drain of tube M1 are connected and then connected to the gate of tube M2. The gate and drain of tube M3 are connected and then connected to the gate of tube M4. The gate of tube M10 is the bias current source signal input terminal. The base of tube Q1 is connected to the base and collector of tube Q2. The resistor R4, the emitter of tube Q2, the emitter of tube Q4 and the source of tube M7 are connected and then grounded. The base of tube Q4 is connected between the resistor R3 and the collector of tube Q2. The positive electrode of Zener diode Q3 is grounded. The gate and drain of tube M5 are connected and then connected to the gate of tube M6. The gate of tube M6 is connected to the other end of capacitor C2 and outputs a source current P27_G. The gate of tube M7 is connected to the drain and outputs a sink current C13_PLUS.

[0009] The tubes M1 to M6 are all PMOS tubes, the tubes M7, M10, and M11 are all NMOS tubes, and the tubes Q1, Q2, and Q4 are all three-stage tubes.

[0010] In the bias current source with a wide voltage range described in the present invention, as a preferred embodiment, the positive temperature coefficient bias current is output by tube Q1, tube Q2 and resistor R4.

[0011] The bias current source with a wide voltage range described in the present invention is preferably configured such that the current passing through the resistor R2 is:

[0012] I R2 =(VDD-V TH1 -V TH3 -V BE1 ) / (R2+R4);

[0013] Among them, V TH1 is the voltage of tube M1, V TH3 is the voltage of tube M3, VBE1 is the voltage of tube Q1;

[0014] I R2 is a positive temperature coefficient current.

[0015] The bias current source with a wide voltage range described in the present invention is preferably configured such that I M3 =I R1 +I R2 ;

[0016] Among them, I M3 is the drain current of tube M3, I R1 is the current flowing through resistor R1;

[0017] And: I M3 =I M4 , I M4 is the drain current of tube M4;

[0018] I M4 =I Q2C +I Q2B +I Q4B , I Q2C is the collector current of tube Q2, I Q2B is the base current of tube Q2, I Q4B is the base current of tube Q4;

[0019] As the temperature increases, I R2 Increase leads to I M3 ,I M4 Increase, I Q2C and I Q2B As the temperature increases, it offsets part of the increase in the base current flowing through tube Q4.

[0020] The bias current source with a wide voltage range described in the present invention, as a preferred embodiment, further includes a start-up circuit, which includes a resistor R5 connected in parallel with the resistor R6 and a capacitor C1 with one end connected to the gate of the tube M10, the cathode of the Zener diode Q3, and the gate of the tube M11, and the other end connected to the ground;

[0021] When the bias current source circuit is powered on, the voltage at the upper end of the capacitor C1 rises and causes the gate voltage of the tube M10 in the bias current generating module to rise to self-start and prevent the bias current generating module from being in a zero state.

[0022] The invention discloses a bias current source with a wide voltage range. As a preferred embodiment, capacitors C1 and C2 can reduce the influence of voltage VDD jitter on the bias current.

[0023] In the bias current source with a wide voltage range described in the present invention, as a preferred embodiment, the tubes M1, M2, M3, and M4 are common-source and common-gate current mirrors and are all high-voltage PMOS tubes.

[0024] In the bias current source with a wide voltage range described in the present invention, as a preferred embodiment, the tube M11 is a high-voltage tube.

[0025] In the bias current source with a wide voltage range described in the present invention, as a preferred embodiment, the resistance value of the resistor R1 is the same as that of the resistor R3, and the ratio of the tube Q1 to the tube Q2 is 6:1.

[0026] In the bias current source with a wide voltage range described in the present invention, as a preferred embodiment, the tubes M5 and M6 form a current mirror.

[0027] The present invention provides a bias current source with a wide power supply range, including a bias current generating module and a bias current output module. Figure 2 As shown, the bias current generating module generates a bias current with a positive temperature coefficient, that is, the bias current increases with the increase of temperature. R5 and C1 in the bias current output module constitute a startup circuit. When the circuit is powered on, the voltage at the upper end of the capacitor C1 rises slowly, so that the gate voltage of M10 in the current generating module rises slowly, preventing the bias current generating module from being in a zero state, causing the bias current to be zero. M3 and M4 in the bias current generating module are high-voltage tubes, and M1, M2, M3, and M4 are high-voltage tubes. The connection mode of the MOS tube (common source and common gate current mirror) can make the bias current change very little with the power supply voltage. M1 and M2 are turned on, and their source and drain voltage difference is very small, and will not be broken down due to the high power supply voltage. The bias current output module has a circuit function of outputting a bias current with high accuracy, wherein the voltage of the Zener diode Q3 decreases with the increase of temperature, so the gate voltage of M11 also decreases with the increase of temperature, causing the source current of M11 to basically not change with temperature. Because the bias current generation module generates a current that increases with temperature, the output bias current P27_G and C13_PLUS in the bias current module output module change very little with temperature. M11 in the bias current output module is a high-voltage tube that can enable the module to work normally at high voltage.

[0028] The present invention has the following advantages:

[0029] (1) The bias current generating module of the present invention generates a bias current, which changes very little within the power supply voltage range of 5.5V to 52V, and also has a self-starting function to prevent the bias current generating module from being in a zero state. The common source and common gate structure formed by the M1 to M4 tubes can reduce the influence of the change of VDD on the output bias current. The capacitors C1 and C2 can reduce the influence of the voltage VDD jitter on the bias current, and have strong anti-interference performance;

[0030] (2) The bias current output module of the present invention can provide a bias current source and a bias current sink as required, and the bias current generation module and the bias current output module cooperate with each other to make the bias current change less with temperature and have high precision.

[0031] (3) The present invention provides a bias current source with a wide power supply range, high precision, strong anti-interference performance, and the ability to provide a source / sink bias current. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a circuit diagram of a traditional resistor voltage divider bias current source;

[0033] Figure 2 A system diagram of a bias current source with a wide voltage range;

[0034] Figure 3 The specific circuit diagram of a bias current source with a wide voltage range is shown in FIG. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] Example 1

[0037] like Figure 2 , 3 As shown, a bias current source with a wide voltage range includes a bias current generating module and a bias current output module; the bias current generating module inputs a C14_PLUS signal;

[0038] like Figure 2 As shown, the bias current generating module generates a bias current with a positive temperature coefficient, that is, the bias current increases with the increase of temperature. R5 and C1 in the bias current output module constitute a startup circuit. When the circuit is powered on, the voltage at the upper end of capacitor C1 rises slowly, so that the gate voltage of M10 in the current generating module rises slowly, preventing the bias current generating module from being in a zero state, causing the bias current to be zero. M3 and M4 in the bias current output module are high-voltage tubes, and M1, M2, M3, and M4 are high-voltage tubes. The connection method of MOS tubes can make the bias current change very little with the power supply voltage. M1 and M2 are turned on, and the voltage difference between their source and drain is very small, and they will not break down due to the high power supply voltage. The positive temperature coefficient bias current is composed of Q1, Q2, and R4 in the bias current generating module, and the current formula is:

[0039]

[0040] Where, ΔV BEAs the temperature rises, it increases. The current through R2 is: I R2 =(VDD-V TH1 -V TH3 -V BE1 ) / (R2+R4), because V TH1 、V TH2 、V BE1 The voltage decreases as the temperature increases, so I R2 It is also a current with a positive temperature coefficient. After the action of the current mirror M1-M4, the drain current of M4 is equal to the collector current of Q2 plus the base current of Q4. Because the collector current of Q2 is also a current with a positive temperature coefficient, that is, the current increases with the increase of temperature, the current flowing into the base of Q4 changes little with the temperature. And because the base of Q4 is connected to the base of Q2, when the temperature rises, the V BE Reduce, Q2's V BE The collector current of Q4 remains unchanged. Similarly, the gate of M10 is connected to the gate of M11, so the source current of M11 changes little with temperature.

[0041] In summary, the output bias current has a small change with temperature and high precision. M11 in the bias current output module is a high-voltage tube that can make the module work normally at high voltage.

[0042] M5 and M6 of the bias current output module form a current mirror, which can provide source current P27_G and sink current C13_PLUS according to different current requirements.

[0043] Resistors R1:R3 are 1:1

[0044] Transistor Q1:Q2 is 6:1

[0045] In this embodiment, the current changes as follows: M3 drain current = current flowing through R1 + current flowing through R2, that is, I M3 =I R1 +I R2 , and because M3 and M4 form a current mirror structure, I M3 =I M4 , because the drain current of M4 = the collector current of Q2 + the base current of Q2 + the base current of Q4, that is, I M4 =I Q2C +I Q2B +I Q4B , so when the temperature increases, the flow through I R2 The current increases, I M3 The current increases, so I M4 Increase, and because the collector current and base current of Q2 increase, it can be concluded from the above formula that the base current flowing through Q4 remains basically unchanged.

[0046] For example: Q at room temperature 1C =5uA, I R2 =2uA, I Q2C =5uA, I Q2B =1uA, I Q4B =1uA, when the temperature rises, Q 1C =6uA, I R2 =3uA, I Q2C =6uA, I Q2B =2uA, so I Q4B =1uA.

[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A bias current source with a wide voltage range, characterized in that: including a bias current generating module and a bias current output module connected; The bias current generating module outputs a positive temperature coefficient bias current to the bias current output module, and the bias current output module cooperates with the bias current generating module to output a source current P27_G and a sink current C13_PLUS and reduce the influence of temperature on the output current; The bias current generating module includes tubes M1 and M2 whose sources are respectively connected to the power supply voltage VDD, a tube M3 whose source is connected to the drain of the tube M1, a tube M4 whose source is connected to the drain of the tube M2, a tube M10 whose drain is connected to the drain of the tube M3, a resistor R1 and a resistor R2 connected in parallel with the source of the tube M10, a tube Q1 whose collector is connected to the other end of the resistor R1 and whose base is connected to the other end of the resistor R2, a resistor R4 connected to the emitter of the tube Q1, a resistor R3 whose one end is connected to the drain of the tube M4, a collector connected to the other end of the resistor R3 and whose base is connected to the other end of the resistor R4. A tube Q2 connected to the ground terminal, a Zener diode Q3 connected to the gate of the tube M10 with its negative electrode, a resistor R6 connected to the power supply voltage VDD at one end, a tube M11 connected to the drain at the other end of the resistor R6 and to the negative electrode of the Zener diode Q3 at its gate, tubes M5 and M6 connected to the source of the tube M11 respectively, a capacitor C2 connected in parallel with the tube M6, a resistor R8 connected to the drain of the tube M5 at one end, a tube Q4 connected to the collector at the other end of the resistor R8, a resistor R9 connected to the drain of the tube M6 at one end, and a tube M7 connected to the gate and drain at the other end of the resistor R9; The gate and drain of tube M1 are connected and then connected to the gate of tube M2. The gate and drain of tube M3 are connected and then connected to the gate of tube M4. The gate of tube M10 is the bias current source signal input terminal. The base of tube Q1 is connected to the base and collector of tube Q2. The resistor R4, the emitter of tube Q2, the emitter of tube Q4 and the source of tube M7 are connected and then grounded. The base of tube Q4 is connected between the resistor R3 and the collector of tube Q2. The positive electrode of Zener diode Q3 is grounded. The gate and drain of tube M5 are connected and then connected to the gate of tube M6. The gate of tube M6 is connected to the other end of capacitor C2 and outputs a source current P27_G. The gate of tube M7 is connected to the drain and outputs a sink current C13_PLUS. The tubes M1 to M6 are all PMOS tubes, the tubes M7, M10, and M11 are all NMOS tubes, and the tubes Q1, Q2, and Q4 are all three-stage tubes.

2. A bias current source with a wide voltage range according to claim 1, characterized in that: The positive temperature coefficient bias current is output by tube Q1, tube Q2 and resistor R4.

3. The bias current source with a wide voltage range according to claim 2, characterized in that: The current through resistor R2 is: I R2 =(VDD-V TH1 -V TH3 -V BE1 ) / (R2+R4); Among them, V TH1 is the voltage of tube M1, V TH3 is the voltage of tube M3, V BE1 is the voltage of tube Q1; I R2 is a positive temperature coefficient current.

4. The bias current source with a wide voltage range according to claim 3, characterized in that: I M3 =I R1 +I R2 ; Among them, I M3 is the drain current of tube M3, I R1 is the current flowing through resistor R1; And: I M3 =I M4 , I M4 is the drain current of tube M4; I M4 =I Q2C +I Q2B +I Q4B , I Q2C is the collector current of tube Q2, I Q2B is the base current of tube Q2, I Q4B is the base current of tube Q4; As the temperature increases, I R2 Increase leads to I M3 ,I M4 Increase, I Q2C and I Q2B As the temperature increases, it offsets part of the increase in the base current flowing through tube Q4.

5. The bias current source with a wide voltage range according to claim 1, characterized in that: It also includes a starting circuit, which includes a resistor R5 connected in parallel with the resistor R6 and a capacitor C1 with one end connected to the gate of the tube M10, the cathode of the Zener diode Q3, and the gate of the tube M11, and the other end connected to the ground; When the bias current source circuit is powered on, the voltage at the upper end of the capacitor C1 rises and causes the gate voltage of the tube M10 in the bias current generating module to rise for self-starting, thereby preventing the bias current generating module from being in a zero state.

6. The bias current source with a wide voltage range according to claim 5, characterized in that: Capacitors C1 and C2 can reduce the impact of voltage VDD jitter on bias current 7. The bias current source with a wide voltage range according to claim 1, characterized in that: The tubes M1, M2, M3, and M4 are common-source and common-gate current mirrors and are all high-voltage PMOS tubes.

8. The bias current source with a wide voltage range according to claim 1, characterized in that: The pipe M11 is a high-pressure pipe.

9. The bias current source with a wide voltage range according to claim 1, characterized in that: The resistance value of resistor R1 is the same as that of resistor R3, and the ratio of tube Q1 to tube Q2 is 6:

1.

10. The bias current source with a wide voltage range according to claim 1, characterized in that: The tube M5 and the tube M6 form a current mirror.

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