Temperature detection circuit

Abstract

The invention discloses a temperature detection circuit, wherein one end of the source and drain of a MOS tube is connected to a working voltage, and the other end is connected to the base of a first NPN transistor and the base of a second NPN transistor; the gate of the MOS tube and the collector of the first NPN transistor are connected to a first bias current source; the emitter of the first NPN transistor is grounded via a resistor; the emitter of the second NPN transistor is short-circuited to ground; the collector of the second NPN transistor and the input end of an inverter are connected to the second bias current source; the output end of the inverter serves as the output end of the temperature detection circuit. The temperature detection circuit of the invention only needs a few components to realize the function of temperature detection, and has a few circuit branches, so the total circuit power consumption is very low, the circuit area is small, and the cost is low.

Description

Technical Field

[0001] The invention relates to semiconductor circuit technology, and in particular to a temperature detection circuit. Background Art

[0002] For integrated circuits with high power consumption, their temperature will be higher. When the temperature is too high, it may affect the reliability of the integrated circuit. Therefore, in some integrated circuits with high power consumption, temperature detection and protection are very important.

[0003] Traditional temperature detection circuits such as Figure 1 As shown, a comparator CMP, a reference voltage VREF and a temperature-related voltage are usually required. The comparator compares the temperature-related voltage and the reference voltage to determine the current temperature of the integrated circuit. The reference voltage VREF needs to be generated by another circuit, and the temperature-related voltage is generated as follows: Figure 1 As shown in , the bias current I1 flows through the transistor Q1, generating a voltage difference VBE between the base and emitter of the transistor. From the transistor characteristics, it can be seen that the VBE voltage has a negative temperature coefficient, usually -2mV / ℃.

[0004] The main disadvantage of the traditional method is that the circuit is relatively complex and requires an external reference voltage and a comparator, which causes the circuit to consume more power and occupy a larger area. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a temperature detection circuit which only needs a few components to realize the temperature detection function and has few circuit branches, so the total circuit power consumption is very low, the circuit area is small, and the cost is low.

[0006] In order to solve the above technical problems, the temperature detection circuit provided by the present invention includes a first bias current source I1, a second bias current source I2, a first NPN transistor Q1, a second NPN transistor Q2, a MOS transistor M1, an inverter INV, and a resistor R1;

[0007] One end of the source and drain of the MOS transistor M1 is connected to the operating voltage VDD, and the other end is connected to the base of the first NPN transistor Q1 and the base of the second NPN transistor Q2;

[0008] The gate of the MOS transistor M1 and the collector of the first NPN transistor Q1 are connected to a first bias current source I1;

[0009] The emitter of the first NPN transistor Q1 is grounded via a resistor R1;

[0010] The emitter of the second NPN transistor Q2 is short-circuited to ground;

[0011] The collector of the second NPN transistor Q2 and the input end of the inverter INV are connected to the second bias current source I2;

[0012] The output terminal TPOUT of the inverter INV serves as the output terminal of the temperature detection circuit.

[0013] Preferably, the temperature detection circuit further includes a temperature output module;

[0014] The temperature output module calculates and outputs a detected temperature value according to the first bias current I1 output by the first bias current source and the second bias current I2 output by the second bias current source when the level of the output terminal TPOUT of the inverter INV is inverted:

[0015] I S1 is the saturation current of the first NPN transistor Q1, k is the Boltzmann constant, q is the electron charge, I S2 is the saturation current of the second NPN transistor Q2, and R1 is the resistance value.

[0016] Preferably, the first bias current I1 output by the first bias current source is smaller than the second bias current I2 output by the second bias current source.

[0017] Preferably, I2=K*I1, where K is a positive integer.

[0018] Preferably, K is 5-15.

[0019] Preferably, the first NPN transistor Q1 is composed of M basic NPN transistors of the same structure connected in parallel;

[0020] The second NPN transistor Q2 is composed of N basic NPN transistors with the same structure connected in parallel;

[0021] I1*N <I2*M。

[0022] Preferably, the resistance of the resistor R1 is 0.5KΩ to 10KΩ.

[0023] Preferably, the MOS tube M1 is an enhancement type MOS tube.

[0024] Preferably, the MOS transistor M1 is an N-channel enhancement type MOS transistor;

[0025] The drain terminal of the MOS transistor M1 is connected to the working voltage VDD, and the source terminal is connected to the base of the first NPN transistor Q1 and the base of the second NPN transistor Q2.

[0026] The temperature detection circuit of the present invention does not require an external reference voltage and a comparator, but only requires a few components to realize the temperature detection function, and has a few circuit branches, so the total circuit power consumption is very low, the circuit area is small, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a traditional temperature detection circuit;

[0029] Figure 2 This is an embodiment of the temperature detection circuit of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1

[0032] like Figure 2 As shown, the temperature detection circuit includes a first bias current source I1, a second bias current source I2, a first NPN transistor Q1, a second NPN transistor Q2, a MOS transistor M1, a resistor R1 and an inverter INV;

[0033] One end of the source and drain of the MOS transistor M1 is connected to the operating voltage VDD, and the other end is connected to the base of the first NPN transistor Q1 and the base of the second NPN transistor Q2;

[0034] The gate of the MOS transistor M1 and the collector of the first NPN transistor Q1 are connected to a first bias current source I1;

[0035] The emitter of the first NPN transistor Q1 is grounded via a resistor R1;

[0036] The emitter of the second NPN transistor Q2 is short-circuited to ground;

[0037] The collector of the second NPN transistor Q2 and the input end of the inverter INV are connected to the second bias current source I2;

[0038] The output terminal TPOUT of the inverter INV serves as the output terminal of the temperature detection circuit.

[0039] Preferably, the temperature detection circuit further includes a temperature output module;

[0040] The temperature output module calculates and outputs a detected temperature value according to the first bias current I1 output by the first bias current source and the second bias current I2 output by the second bias current source when the level of the output terminal TPOUT of the inverter INV is inverted:

[0041] I S1 is the saturation current of the first NPN transistor Q1, k is the Boltzmann constant, q is the electron charge, I S2 is the saturation current of the second NPN transistor Q2, and R1 is the resistance value.

[0042] In the temperature detection circuit of the first embodiment, the first bias current I1 output by the first bias current source flows through the first NPN transistor Q1, and the emitter current of the first NPN transistor Q1 is I1, that is, Among them I S1 is the saturation current of the first NPN transistor Q1, V T is the thermal voltage, Where k is the Boltzmann constant, T is the absolute temperature, and q is the electron charge. From this, we can get the base-emitter voltage difference of the first NPN transistor Q1: The first bias current I1 flows through the resistor R1 at the same time, and the voltage generated on the resistor R1 is I1R1. Therefore, the voltage VB at the connection point between the base of the first NPN transistor Q1 and the base of the second NPN transistor Q2 is: V B =V BE1 +I1R1. The voltage at the connection point VB is also applied to the base of the second NPN transistor Q2, so the emitter current I e2 It is related to the voltage of the connection point VB, that is, Where I S2 is the saturation current of the second NPN transistor Q2. e2 is equal to the second bias current I2 output by the second bias current source, that is, Then we can get Where V BE2th is the base-emitter voltage difference of the second NPN transistor Q2 when the emitter current of the second NPN transistor Q2 is equal to I2. Further, we can get: V B -V BE2th =V BE1 +I1R2-V VBE2th ; Substitute V BE1 and V BE2th ,have to:

[0043]

[0044] Since I1 < I2, then V B -V BE2th The voltage has a negative temperature coefficient. When V B -V BE2th = 0, we get:

[0045]

[0046]

[0047] When the temperature < T0, V B -V BE2th > 0, so V B > V BE2th , the emitter current I e2 > I2 of the second NPN transistor Q2. The collector voltage VC2 of the second NPN transistor Q2 will be pulled down. After passing through the inverter INV, the output terminal TPOUT of the inverter INV outputs a high level. When the temperature > T0, V B -V BE2th < 0, so V B < V BE2th , the emitter current I e2 < I2 of the second NPN transistor Q2. The collector voltage VC2 of the second NPN transistor Q2 will be pulled up. After passing through the inverter INV, the output terminal TPOUT of the inverter INV outputs a low level. Gradually change the first bias current I1 output by the first bias current source or the second bias current I2 output by the second bias current source. Thus, according to the first bias current I1 and the second bias current I2 when the level of the output terminal TPOUT of the inverter INV is inverted, the temperature when the level of the output terminal TPOUT of the inverter INV is inverted can be determined:

[0048] The temperature detection circuit of Embodiment 1 does not require an external reference voltage and a comparator, and only requires very few components to achieve the function of temperature detection. The circuit branches are very few, so the total circuit power consumption is very low, the circuit area is small, and the cost is low.

[0049] Embodiment 2

[0050] Based on the temperature detection circuit of Embodiment 1, the first bias current I1 output by the first bias current source is less than the second bias current I2 output by the second bias current source.

[0051] Preferably, I2 = K * I1, where K is a positive integer.

[0052] Preferably, K is 5 to 15. For example, K is 6, 8, or 10.

[0053] Implementation Three

[0054] Based on the temperature detection circuit of the second embodiment, the first NPN transistor Q1 is composed of M basic NPN transistors with the same structure connected in parallel, and it can be obtained that I S1 =MI S0 , where I S0 is the saturation current of the basic NPN transistor;

[0055] The second NPN transistor Q2 is composed of N basic NPN transistors with the same structure connected in parallel, so I S2 =NI S0 , where I S0 is the saturation current of the basic NPN transistor;

[0056] I1*N <I2*M。

[0057] Preferably, the resistance of the resistor R1 is 0.5KΩ to 10KΩ.

[0058] Preferably, the MOS tube M1 is an enhancement type MOS tube.

[0059] Preferably, the MOS transistor M1 is an N-channel enhancement type MOS transistor;

[0060] The drain terminal of the MOS transistor M1 is connected to the working voltage VDD, and the source terminal is connected to the base of the first NPN transistor Q1 and the base of the second NPN transistor Q2.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A temperature detection circuit, characterized in that: It includes a first bias current source (I1), a second bias current source (I2), a first NPN transistor (Q1), a second NPN transistor (Q2), a MOS transistor (M1), an inverter (INV), a resistor (R1) and a temperature output module; One end of the source and drain of the MOS tube (M1) is connected to the working voltage (VDD), and the other end is connected to the base of the first NPN transistor (Q1) and the base of the second NPN transistor (Q2); The gate of the MOS tube (M1) and the collector of the first NPN transistor (Q1) are connected to a first bias current source (I1); The emitter of the first NPN transistor (Q1) is grounded via a resistor (R1); The emitter of the second NPN transistor (Q2) is short-circuited to ground; The collector of the second NPN transistor (Q2) and the input end of the inverter (INV) are connected to a second bias current source (I2); The output end (TPOUT) of the inverter (INV) serves as the output end of the temperature detection circuit; The temperature output module calculates and outputs a detected temperature value according to a first bias current I1 output by a first bias current source and a second bias current I2 output by a second bias current source when the level of an output terminal (TPOUT) of an inverter (INV) is inverted: I S1 is the saturation current of the first NPN transistor (Q1), k is the Boltzmann constant, q is the electron charge, I S2 is the saturation current of the second NPN transistor (Q2), and R1 is the resistance value.

2. The temperature detection circuit according to claim 1, characterized in that: The first bias current I1 output by the first bias current source is smaller than the second bias current I2 output by the second bias current source.

3. The temperature detection circuit according to claim 2, characterized in that: I2=K*I1, K is a positive integer.

4. The temperature detection circuit according to claim 3, characterized in that: K is 5 to 15.

5. The temperature detection circuit according to claim 2, characterized in that: The first NPN transistor (Q1) is composed of M basic NPN transistors of the same structure connected in parallel; The second NPN transistor (Q2) is composed of N basic NPN transistors of the same structure connected in parallel; I1*N <I2*M。 6. The temperature detection circuit according to claim 1, characterized in that: The resistance of the resistor (R1) is 0.5KΩ to 10KΩ.

7. The temperature detection circuit according to claim 1, characterized in that: The MOS tube (M1) is an enhanced MOS tube.

8. The temperature detection circuit according to claim 1, characterized in that: The MOS tube (M1) is an N-channel enhancement type MOS tube; The drain terminal of the MOS tube (M1) is connected to the operating voltage (VDD), and the source terminal is connected to the base of the first NPN transistor (Q1) and the base of the second NPN transistor (Q2).

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