Temperature-based current limiting protection circuit and chip

Abstract

The application belongs to the field of electronic technology, and provides a temperature-based current-limiting protection circuit and a chip, wherein the circuit comprises a feedback control module, a current sampling module and a reference signal generation module; the current sampling module is connected to the feedback control module; the feedback control module is connected to the reference signal generation module; the current sampling module is used to collect an output signal of the circuit to obtain a sampling signal; the reference signal generation module is used to generate a reference signal according to temperature; and the feedback control module is used to compare the reference signal with the sampling signal and adjust the output signal according to the comparison result. Thus, different reference signals can be generated according to different temperatures, the current-limiting threshold of the current-limiting protection circuit can change with temperature, and the circuit can be applied to a wide range of working voltages.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and in particular to a temperature-based current limiting protection circuit and chip. Background Technology

[0002] To protect chips from burning out due to excessive current, current-limiting protection circuits are incorporated into them. These circuits typically sample the output current / voltage of the output circuit, compare the sampled output current / voltage with a reference output current / voltage, and then adjust the input current / voltage of the output circuit to limit the output current, thus achieving output current limiting. For example, if the output circuit is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the circuit samples the gate voltage of the output transistor, compares the sampled gate voltage with a reference voltage, and then adjusts the gate voltage of the output transistor to limit the voltage between the gate and source (gate-source voltage), thereby achieving output current limiting.

[0003] However, current current-limiting protection circuits all use fixed reference voltages, meaning the current-limiting threshold is fixed, while more and more circuits are operating with wider voltage ranges. When the operating voltage is high, the voltage across the drain and source of the power transistor (drain-source voltage) is also high. If the current-limiting threshold is too high, it will cause excessive current to flow through the power transistor, resulting in high power consumption and potentially burning out the chip. When the operating voltage is low, the drain-source voltage of the power transistor is low, and the power consumption is low, requiring a higher current-limiting threshold to ensure a higher output current and improve the circuit's load-carrying capacity.

[0004] In other words, a lower current limiting threshold is needed when the operating voltage is high to prevent the chip from burning out. Conversely, a higher current limiting threshold is needed when the operating voltage is low to improve the circuit's load-carrying capacity. However, since the circuit's current limiting threshold is a constant value, it is difficult to balance both scenarios. Summary of the Invention

[0005] This application provides a temperature-based current limiting protection circuit and chip, which can generate different reference currents or reference voltages according to different temperatures, thereby enabling the current limiting threshold of the current limiting protection circuit to change with temperature, and the circuit can be applied to a wide range of operating voltages.

[0006] In a first aspect, a temperature-based current-limiting protection circuit is provided, characterized in that the circuit includes a feedback control module, a current sampling module, and a reference signal generation module. The current sampling module is connected to the feedback control module, and the feedback control module is connected to the reference signal generation module. The current sampling module is used to acquire the output signal of the circuit to obtain a sampled signal; the reference signal generation module is used to generate a reference signal based on the temperature; and the feedback control module is used to compare the reference signal with the sampled signal and adjust the output signal according to the comparison result.

[0007] In the above scheme, the temperature-based current-limiting protection circuit can generate different reference signals according to different temperatures, so that the current-limiting threshold of the current-limiting protection circuit can change with temperature, and thus the circuit can be applied to a wide range of operating voltages. Specifically, when the operating voltage is low, the output transistor power is low and the circuit temperature is low, resulting in a higher reference signal, allowing the circuit to handle a larger load under normal operating conditions. Conversely, when the operating voltage is high, the output transistor power is high and the circuit temperature is also high, resulting in a lower reference signal, preventing the circuit from operating at excessive current and thus avoiding damage to the components in the circuit. Therefore, this temperature-based current-limiting protection circuit can be applied to circuits with a wide operating voltage range.

[0008] In conjunction with the first aspect, in some implementations, the output signal is an output current or an output voltage; the sampling signal is a sampling current or a sampling voltage; the reference signal is a reference current or a reference voltage; and the comparison result is a current comparison result or a voltage comparison result.

[0009] In conjunction with the first aspect, in some implementations, the reference signal generation module is used to generate a temperature reference signal based on the temperature. When the temperature reference signal is less than a first temperature threshold, the reference signal generation module determines the reference signal as the first reference signal. When the temperature reference signal is greater than the first temperature threshold and less than a second temperature threshold, the reference signal generation module determines the reference signal as the second reference signal, which is greater than the first reference signal. When the temperature reference signal is greater than the second temperature threshold and less than a third temperature threshold, the reference signal generation module determines the reference signal as the third reference signal, which is greater than the second reference signal. When the temperature reference signal is greater than the third temperature threshold, the reference signal generation module determines the reference signal as the fourth reference signal, which is greater than the third reference signal.

[0010] In conjunction with the first aspect, in some implementations, the feedback control module is used to compare the reference signal with the sampled signal. When the sampled signal does not reach the reference signal, the feedback control unit determines to adjust the output signal according to the first control signal. When the sampled signal reaches the reference signal, the feedback control unit determines to adjust the output signal according to the second control signal. The first control signal makes the output signal less than a set threshold, and the second control signal makes the output signal equal to the set threshold.

[0011] In conjunction with the first aspect, in some implementations, the reference signal generation module is also used to generate a logic signal based on the reference current source and the second control signal, and the logic signal is used to control the reference signal to remain unchanged.

[0012] In conjunction with the first aspect, in some implementations, the reference signal generation module includes a temperature acquisition element, which is used to generate a temperature reference signal that is positively or negatively correlated with the current temperature.

[0013] In conjunction with the first aspect, in some implementations, the temperature acquisition element is one or more transistors, and the reference signal generation module further includes a control logic module, a first comparator, a second comparator, a third comparator, a first control switch, a second control switch, a third control switch, a first current source, a second current source, and a third current source; and the base and collector of the one or more transistors are short-circuited and connected to the inverting input terminals of the first comparator, the second comparator, and the third comparator. The output terminals of the first comparator, the second comparator, and the third comparator are connected to the control logic module, and the output terminals of the control logic module are respectively connected to the first control switch, the second control switch, and the third control switch. The first control switch is connected to the first current source, the second control switch is connected to the second current source, and the third control switch is connected to the third current source.

[0014] In conjunction with the first aspect, in some implementations, the control logic module includes a low-voltage power supply indication signal, an inverter, a first RS flip-flop, a second RS flip-flop, a third RS flip-flop, a first AND gate, a second AND gate, a first NOR gate, a second NOR gate, and a third NOR gate. The low-voltage power supply indication signal is connected to the input of the inverter. The output of the inverter is connected to the set terminals of the first RS flip-flop, the second RS flip-flop, and the third RS flip-flop, respectively. The logic signal is connected to the first input of the first NOR gate, the second NOR gate, and the third NOR gate. The output of the first comparator is connected to the reset terminal of the first RS flip-flop and the second input of the first NOR gate. The output of the second comparator is connected to the first input of the first AND gate and the second input of the second NOR gate. The output of the third comparator is connected to the first input of the second AND gate and the second input of the third NOR gate. The NOT signal of the output of the first RS flip-flop is connected to the second input of the first AND gate. The NOT signal of the output of the second RS flip-flop is connected to the second input of the second AND gate. The output of the first AND gate is connected to the reset terminal of the second RS flip-flop. The output of the second AND gate is connected to the reset terminal of the third RS flip-flop.

[0015] In a second aspect, a chip is provided, wherein a temperature-based current-limiting protection circuit as described in any one of the first aspects is formed.

[0016] Thirdly, an electronic device is provided, characterized in that the electronic device includes a chip in which a temperature-based current limiting protection circuit as described in any of the first aspects is formed. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0018] Figure 1 This is a schematic diagram of the structure of a prior art current-limiting protection circuit provided in an embodiment of this application;

[0019] Figure 2 This is a circuit diagram of a prior art current limiting protection circuit provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a temperature-based current limiting protection circuit provided in an embodiment of this application;

[0021] Figure 4 This is a circuit diagram of a temperature-based current limiting protection circuit provided in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the structure of a reference signal generation module provided in an embodiment of this application;

[0023] Figure 6 This is a circuit diagram of a reference signal generation module provided in an embodiment of this application;

[0024] Figure 7 This is a circuit diagram of a control logic module provided in an embodiment of this application;

[0025] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0026] The illustrative embodiments of this application include, but are not limited to, a temperature-based current limiting protection circuit and a chip.

[0027] To protect chips from damage due to excessive current, current-limiting protection circuits are incorporated into them. Examples include operational amplifier output short-circuit current limiting circuits and low-dropout linear regulators. Specifically, as load current requirements increase, the current flowing through the power transistors in the chip also increases. To prevent damage caused by a sudden decrease in circuit load leading to a sudden increase in chip current or a short circuit at the chip's output, current-limiting protection circuits are integrated within the chip. The function of this current-limiting protection circuit is to activate when the current through the protected device exceeds a set threshold, limiting the power transistor's output current to the threshold point. As the power transistor current gradually decreases, the system automatically returns to normal operation, thus protecting the chip.

[0028] like Figure 1 As shown, Figure 1 An exemplary schematic diagram of a current limiting protection circuit is shown. The current limiting protection circuit includes a power stage sampling module and a feedback control module. The sampling module samples the gate voltage of the output transistor or samples the output current at a certain ratio. The sampled signal is compared with a reference current or voltage. The feedback control module adjusts the gate voltage of the output power transistor to limit the gate-source voltage of the output transistor, thereby achieving output current limiting.

[0029] In some embodiments, the current limiting protection circuit can be as follows: Figure 1As shown, MOSFETs M1 and M2 are output transistors, i.e., power transistors. Specifically, output transistor M1 is a P-channel MOSFET (positive channel MOS), and output transistor M2 is an N-channel MOSFET (negative channel MOS). Current limiting protection circuits generally include a sampling module and a feedback control module. Taking the protection of M1 in the power output stage as an example, the sampling module samples the gate voltage of M1 or samples the drain and source currents (i.e., drain-source current) of M1 at a certain ratio. Then, the feedback control module obtains the sampling data from the sampling module, compares the sampled data with a reference current or voltage, and determines whether to adjust the gate voltage of M1 to limit the gate and source voltages of the output transistor M1, thereby limiting the output current.

[0030] The principle of the current current limiting protection circuit is introduced below. Figure 2 Taking the circuit diagram shown as an example, Figure 2 This includes MOSFETs M1, M2, M3, M4, and M5, and error amplifier EA1. The positive input terminal of EA1 is connected to the feedback voltage V. FB The negative input terminal is connected to the reference voltage V. REF The output terminal is connected to the gate of M1. The gate of M1 is also connected to the drain of M2 and the gate of M3, respectively. The drain of M1 is connected to I. out The input terminal of M2. The drain of M2 is connected to the gate of M3, and the gate of M2 is connected to I. limited The output terminal of M3. The drain of M3 is connected to the drain of M4, the gate of M4, and the gate of M5, respectively. The gate of M4 is connected to the gate of M5, and the drain of M5 is connected to the gate of M2 and I. limited The output terminals are connected. The source of M1, the source of M2, the source of M3, and I... limited The input terminals are connected to the power supply voltage, respectively. The source of M4, the source of M5, and I... out The output terminals are connected to the power supply ground terminal respectively.

[0031] Where M1 is the output transistor, and the output current is I. out Because the gate and source voltages of M3 and M1 are equal, it is possible to achieve proportional sampling of the output current of M1 by M3, that is, the drain current of M3 is proportional to I. out The ratio is a fixed value, for example, the ratio of the drain current of M3 to Iout is 1:N. Then, the drain current of M3 passes through a current mirror composed of M4 and M5, and is then mirrored onto the drain of M5. The drain current of M5 (sampling current Iout) is then... sample ) and the set current limiting threshold I limited Compare. When the sampling current I... sample When it is large, i.e., Isample >I limited When the voltage at point A is pulled low, M2 is turned on. By adjusting the gate voltage of the output transistor M1 through M2, the output current I is reduced. out When the sampling current I sample Decrease, less than the current limiting threshold I limited At that time, i.e., I sample limited When the voltage at point A is pulled high, transistor M2 is turned off, and the current-limiting circuit becomes ineffective, allowing the circuit to operate normally. This achieves current limiting by adjusting the gate voltage of the output transistor when the output current is large.

[0032] However, current circuits operate over a wide voltage range. When the voltage across the drain and source of the power transistor (drain-source voltage) is high, an excessively high current limiting threshold can lead to excessive current flowing through the power transistor, resulting in significant power consumption and chip burnout. Therefore, when the power transistor's drain-source voltage is high, a lower current limiting threshold is needed to prevent circuit damage. Conversely, when the power transistor's drain-source voltage is low and power consumption is low, a higher current limiting threshold is required to allow for higher output current and improve the circuit's load-carrying capacity. Figure 1 or Figure 2 The circuit shown has a constant current limiting threshold, making it difficult to accommodate both of the above situations.

[0033] To address the issue that current current limiting protection circuits have fixed current limiting thresholds, making them unsuitable for circuits with a wide operating voltage range, this application provides a temperature-based current limiting protection circuit and chip. This circuit utilizes the voltage difference V between the base (B) and emitter (E) of a transistor. BE The characteristic of being negatively correlated with temperature, and therefore based on V BE By adjusting the reference current, when the sampling current of the output transistor exceeds the reference current, the output current of the output transistor is adjusted, thereby regulating the current limiting threshold based on chip temperature changes. In this way, when the operating voltage is low, the drain-source voltage of the output transistor is low, resulting in low output transistor power and a low chip temperature, thus allowing V to... BE A higher voltage corresponds to a one-unit increase in the reference current, allowing for a larger load to be driven under normal operating conditions. However, when the operating voltage is high, the drain-source voltage of the output transistor is high, resulting in high output transistor power and a higher chip temperature, which in turn affects V. BE The reference current is reduced by one unit to prevent excessive operating current and potential damage to components. This, in turn, allows the temperature-based current-limiting protection circuit to be applied to circuits with a wider operating voltage range.

[0034] ​When the sampling current exceeds the current limiting threshold (i.e., the output current is large) and the chip temperature rises to a limit value, the circuit reduces the output current by adjusting the gate voltage of the output transistor using a MOSFET. However, if the circuit temperature continues to rise, the reference current will continue to decrease, meaning the current limiting threshold will decrease. This will further reduce the output current of the output transistor, thus lowering the chip temperature. As the output current decreases, the power of the output transistor decreases, the chip temperature decreases, and the reference current will rise again. Then, the circuit output current gradually increases, causing the chip temperature to rise again, and the reference current to decrease again. This cycle repeats, with the circuit's temperature, current limiting threshold, and output current all entering a state of repeated increases and decreases.

[0035] To prevent the reference current from constantly changing with temperature, thus causing the current limiting threshold to also change, this application also provides a current limiting state detection circuit. When the circuit's output current is high, and the MOSFET adjusts the gate voltage of the output transistor to reduce the output current, to prevent the reference current from decreasing and then increasing again due to the decrease in chip temperature, causing the current limiting threshold to decrease and then increase again, the current limiting state detection circuit will generate a logic signal. This logic signal is generated based on the current of the MOSFET that is adjusted. This logic signal controls the reference current to no longer change with temperature after the current limiting is triggered, thereby preventing the current limiting threshold from constantly changing and the range of the circuit's output current from being unstable.

[0036] The structure of the temperature-based current-limiting protection circuit provided in this application is described below. For example... Figure 3 As shown, this temperature-based current-limiting protection circuit includes a current-limiting state detection module, a reference signal generation module, a feedback control module, a current sampling module, and a power output stage module. The current sampling module collects the output current of the output transistor in the power output stage module and transmits the sampled current to the feedback control module. The reference signal generation module generates a reference current, which the feedback control module compares with the sampled current. Based on the comparison result, it adjusts the voltage of the output transistor via a MOSFET, thereby adjusting the circuit's output current. The current-limiting state detection circuit generates a logic signal based on the current of the MOSFET used to adjust the output transistor voltage. This logic signal controls the reference current to remain constant regardless of temperature after current limiting is triggered, preventing continuous changes in the current-limiting threshold.

[0037] The following is combined with Figure 4 The specific circuit diagram of the temperature-based current limiting protection circuit described above is illustrated with an example.

[0038] The power output stage module is exemplified by a Class AB power amplifier, specifically composed of a PMOS transistor MP5, an NMOS transistor MN5, and a driver circuit. MP5 is the output transistor. The source of MP5 is connected to the power supply VEX, and the drain is connected to the output terminal V. out Simultaneously, the drain of MN5 is connected, and the gate of MP5 is connected to the gate and drive circuit of POM transistor MP4 in the current sampling module; the gate of MN5 is connected to the drive circuit, and the source is grounded.

[0039] The current sampling module consists of a PMOS transistor MP4, where the source of MP4 is connected to the power supply VEX, and the drain is connected to the drain of the NMOS transistor MN1 in the feedback control module. The gate voltage of MP4 is equal to the gate voltage of the output transistor MP5, and its size is 1 / N of MP5, so that when MP5 is turned on, the sampling current I is... sense For I out / N.

[0040] The feedback control module consists of NMOS transistors MN1, MN2, and MN4, a PMOS transistor MP3, and a capacitor C0. The gate and drain of transistor MN1 are shorted and connected to the gate of MN2; the source of MN1 is grounded. The source of transistor MN2 is grounded, and its drain is connected to the source of MN4. The gate of transistor MN4 is connected to an external bias voltage VBN1, and its drain is connected to a reference current I. REF The output terminal, the gate of MP3 transistor, one end of capacitor C0, and the gate of MP1. Reference current I. REF The input terminal of the MP3 transistor is connected to the power supply VEX. The source of the MP3 transistor is connected to the power supply VEX, and the drain of the MP3 transistor is connected to the other end of the capacitor C0, which is also connected to the gate of the MP4 transistor and the gate of the MP5 transistor.

[0041] Among them, the size of transistor MN2 is 1 / M of that of transistor MN1, and the feedback control circuit uses the sampled current I... sense After being reduced by a factor of M, it is compared with the reference current I. REF In comparison, MN4 is a high-voltage clamping transistor, preventing excessive voltage at the drain of the low-voltage transistor MN2. When I sense The value of / MN is greater than I. REF At this time, the MP3 transistor is turned on, discharging the charge from the gate of the output transistor and stabilizing it at the set voltage, thus obtaining a fixed output current I. out This enables flow control protection. Figure 4 Reference current I in REF The relationship between the output current and the output current can be referred to the following formula (1):

[0042] I OUT =M*N*I REF (1)

[0043] In other words, the feedback control module will use the reference signal (I) REF ) and sampled signal (I sense When the sampled signal is compared with the reference signal ( / MN), the MP3 of the feedback control unit outputs a first control signal to the gate of the output transistor when the sampled signal does not reach the reference signal. When the sampled signal reaches the reference signal, the MP3 of the feedback control unit outputs a second control signal to the gate of the output transistor, making the output signal equal to the set threshold I. out .

[0044] The current limiting state detection module consists of PMOS transistors MP1 and MP2, and NMOS transistors MN3 and MN6. The source of transistor MP1 is connected to the power supply, and its drain is connected to the source of transistor MP2. The gate of transistor MP2 is connected to the bias voltage V. BP2 Its drain is connected to the drain of MN3. The gate and drain of MN3 are shorted, and its source is grounded. The gate of MN6 is connected to the gate of MN3, its source is grounded, and its drain generates the output signal I. limit_gen When the current limiting circuit is not working, the gate voltage of MP3 is the power supply voltage, and the output current of MN6 is zero. When the current limiting circuit is working, I... limit_gen Output a current proportional to the MP3 current.

[0045] It should be understood that Figure 4 This is just one implementation of the temperature-based current-limiting protection circuit. In other embodiments, the current sampling module can also be equipped with other clamping circuits to ensure the accuracy of current sampling. Alternatively, in some other embodiments, the voltage of the output transistor can also be sampled. This application does not specifically limit the specific structure and components of the circuit.

[0046] The following is combined with Figure 5 introduce Figure 4 Reference current I REF The generation of [something] will be explained in detail. For example... Figure 5 As shown, a reference current I is generated. REF The circuit module, namely the reference signal generation module, includes a temperature detection module and a reference current selection module.

[0047] The temperature detection module primarily utilizes the characteristic that a certain parameter of the temperature acquisition element changes with temperature, outputting a voltage value that varies with temperature. For example, the temperature detection module can use one or more transistors, utilizing the voltage difference V between the transistor's base and emitter. BE The characteristic of being negatively correlated with temperature is used to generate voltage values ​​that vary with temperature.

[0048] The reference current selection module is used to generate different magnitudes of reference current I based on the voltage value output by the temperature detection module, i.e., the temperature reference signal, and then using control logic circuitry.REF . Wherein, the control logic circuit can control the closing of a plurality of switches through the output voltage of the temperature detection module, the plurality of switches are each connected to different current sources, so that the reference current selection module generates output currents of different magnitudes, that is, the reference current I REF .

[0049] Hereinafter, in combination with Figure 6 , the specific circuit diagram for generating the reference current I REF , that is, the circuit diagram of the reference signal generating module, will be described by way of example.

[0050] The temperature detection circuit comprises a current source I5, an NPN-type triode Q1 and an NPN-type triode Q2. An emitter of the triode Q2 is grounded, a base and a collector of the triode Q2 are short-circuited and connected to an emitter of the triode Q1. A base and a collector of the triode Q1 are short-circuited and connected to an output end of the current source I5, and are simultaneously connected to inverting input ends of comparators A1, A2 and A3 of the reference current selection module, and an upper end of the current source I5 is connected to a power supply VIN. Wherein, since the V BE voltage of is negatively correlated with temperature, the higher the temperature is, the V BE will be smaller.

[0051] The reference current selection module comprises comparators A1, A2 and A3, a control logic module, current sources I1 to I4, I6, as well as Figure 4 a signal I generated by current-limiting state detection limit_gen and switches S1 to S3. The comparator A1 can also be referred to as a first comparator, the comparator A2 can also be referred to as a second comparator, and the comparator A3 can also be referred to as a third comparator. The current source I1 can also be referred to as a first current source, the current source I2 can also be referred to as a second current source, and the current source I3 can also be referred to as a third current source. The switch S1 can also be referred to as a first control switch, the switch S2 can also be referred to as a second control switch, and the switch S3 can also be referred to as a third control switch.

[0052] Wherein, the comparators are configured to compare the voltage value output by the temperature detection module with a preset voltage value, so as to generate an indication bit representing the comparison result, and the current temperature grade to which the current temperature belongs can be determined according to the indication bit. A non-inverting input end of the comparator A1 is connected to a reference voltage V REF1 , an output end of the comparator A1 is configured to send an indication bit of T>T1 to the control logic module. A non-inverting input end of the comparator A2 is connected to a reference voltage V REF2 , an output end of the comparator A2 is configured to send an indication bit of T>T2 to the control logic module. A non-inverting input end of the comparator A3 is connected to a reference voltage V REF3 , an output end of the comparator A3 is configured to send an indication bit of T>T3 to the control logic module, wherein T1<T2<T3. The current source I6 and I limit_genthe comparison signal limit is also sent to the control logic module, and the output signals s1, s2 and s3 of the control logic module correspondingly control the switching of switches S1, S2 and S3, and the finally output I REF , I REF can be calculated with reference to the following formula (2), and the values of s1, s2 and s3 are 0 or 1.

[0053] I REF =I4+s1*I1+s2*I2+s3*I3 (2)

[0054] Therefore, the voltage value V that changes with temperature is output through triodes Q1 and Q2 BE , and then the closing of the switch is controlled through the comparator and the control logic module, so that I REF can change its magnitude with the change of temperature. Wherein, according to formula (2), I REF can have values of I4, I4+I1, I4+I1+I2, I4+I1+I2+I3.

[0055] That is, when the temperature reference signal is less than the first temperature threshold (T<T1), the reference signal generation module determines that the reference signal is the first reference signal (I4).

[0056] When the temperature reference signal is greater than the first temperature threshold and less than the second temperature threshold (T>T1), the reference signal generation module determines that the reference signal is the second reference signal (I4+I1), and the second reference signal is greater than the first reference signal.

[0057] When the temperature reference signal is greater than the second temperature threshold and less than the third temperature threshold (T>T2), the reference signal generation module determines that the reference signal is the third reference signal (I4+I1+I2), and the third reference signal is greater than the second reference signal.

[0058] When the temperature reference signal is greater than the third temperature threshold (T>T3), the reference signal generation module determines that the reference signal is the fourth reference signal (I4+I1+I2+I3), and the fourth reference signal is greater than the third reference signal.

[0059] In addition, the reference signal generation module can also generate I corresponding to the second control signal according to the reference current source (current source I6) limit_gen to generate a logic signal (limit), which can be used to control the reference signal to remain unchanged.

[0060] It should be understood that Figure 4 it is only one implementation of the current protection circuit. In other embodiments, the switches S1, S2 and S3 can also be NMOS transistors or PMOS transistors.

[0061] Furthermore, the temperature sensing circuit can contain one or more transistors. The more transistors there are, the more V they generate based on temperature changes. BE This will reduce the error and make the circuit's temperature detection more accurate. Figure 6 The example shown uses two transistors, but this application does not specify the number of transistors in the temperature detection circuit.

[0062] Similarly, the comparators in the above circuit can be one or more, the number of switches can be one or more, and the number of current sources connected to the switches can also be one or more. The number of comparators corresponds to the number of switches. It should be understood that the more comparators there are, the more temperature levels can be determined, resulting in more indicator bits output to the control logic signals, enabling the control of more switches, and thus... REF There are many possible values ​​for it.

[0063] The following is an introduction Figure 6 The specific circuit structure of the control logic module.

[0064] like Figure 7 As shown, the control logic module includes an inverter I1, reset / set triggers (RS triggers) I3, I6, and I9, input AND gates I4 and I7, and input NOR gates I2, I5, and I8. I3 can also be called the first RS trigger, I6 the second RS trigger, I9 the third RS trigger, I4 the first AND gate, I7 the second AND gate, I2 the first NOR gate, I5 the second NOR gate, and I8 the third NOR gate.

[0065] Specific connections include, Figure 6The limit signal is connected to one input of NOR gates I2, I5, and I8. The output of comparator A1 (indicating T>T1) is connected to the reset terminal (Reset terminal, R terminal) of I3, and also to one input of NOR gate I2. The internal low-voltage power supply indicator signal VIN_OK is connected to the input of inverter I1. The output of I1 is connected to the first set terminal (set terminal, S terminal) of I3, I6, and I9 respectively. The output of I2 is connected to the second set terminal (second S terminal) of I3. One output signal of I3 is the S1 signal, and the other output is the inverse signal of S1. S1 controls switch S1. The inverse signal of S1 is connected to one input of AND gate I4. The output of comparator A2 (indicating T>T2) is connected to the other input of AND gate I4, and also to the other input of NOR gate I5. The output of I4 is connected to the R terminal of RS flip-flop I6, and the output of I5 is connected to the second S terminal of I6. One output of I6 is signal S2, which controls switch S2. Another signal, the inverse of S2, is connected to the input of AND gate I7. The output of comparator A3 (indicating T>T3) is connected to another input of I7, and simultaneously to another input of NOR gate I8. The output of I7 is connected to the R terminal of RS flip-flop I9, and the output of I8 is connected to the second S terminal of I9. The output signal of I9 is ​​S3, which controls switch S3.

[0066] The internal low-voltage power supply indicator signal VIN_OK is used to set appropriate initial values ​​for the control logic. Specifically, before the internal power supply is established, VIN_OK is low, and signals s1, s2, and s3 are all high. At this time, all current sources are connected, and the reference current source is the set maximum value I. REF =I4+I1+I2+I3.

[0067] When VIN_OK goes high, the RS flip-flop output remains high, and the current limiting threshold remains unchanged. If the chip operates at a low ambient temperature, the drain-source voltage of the output transistor is small, resulting in a small temperature rise, and the normal operating load can be large. If the chip operates at a low ambient temperature but the drain-source voltage of the output transistor is large, the current limiting threshold will initially remain high, without affecting the normal operation of the chip. When the circuit output is short-circuited to ground, excessive power on the output transistor causes a temperature rise until the junction temperature > T1. At this point, S1 is low, switch S1 is open, and the current limiting threshold decreases. The corresponding reference current value at this time is I. REF = I4 + I2 + I3. If switch S1 is already closed, but the junction temperature continues to rise to >T2, then S2 output will be low, and the reference current value will further decrease to I. REF = I4 + I3. If switch S2 is already closed, and the junction temperature continues to rise to >T3, then at this time, the output of S3 is low, and the reference current decreases to the minimum value I. REF=I4. The corresponding short-circuit current and temperature rise also decrease. The value of I4 needs to ensure that the chip can operate in a safe state. When the chip exits the current limiting state (limit = 0) and the temperature is below the threshold, the current limiting value gradually returns to its initial value. When the ambient temperature is high, the current limiting value of the circuit also decreases as the temperature decreases.

[0068] Furthermore, the control logic module can convert the signals output by comparators A1, A2, and A3 into the closing of control switches. The switches are connected to current sources, which allows the output reference current to have multiple levels, thus enabling the current limiting threshold to be adjusted according to temperature changes.

[0069] In summary, the temperature-based current-limiting protection circuit provided in this application has a smaller drain-source voltage of the output transistor when the operating voltage is low. At this time, the output transistor power is low, the chip temperature is low, and thus V BE A higher voltage corresponds to a one-unit increase in the reference current, allowing for a larger load to be driven under normal operating conditions. However, when the operating voltage is high, the drain-source voltage of the output transistor is high, resulting in high output transistor power and a higher chip temperature, which in turn affects V. BE The reference current is reduced by one unit to prevent excessive operating current and potential damage to components. This, in turn, allows the temperature-based current-limiting protection circuit to be applied to circuits with a wider operating voltage range.

[0070] On the other hand, embodiments of the present invention also propose a chip having a temperature-based current-limiting protection circuit as described in any of the above embodiments. The chip can be an analog-to-digital converter chip, an interface chip, or a power management chip.

[0071] On the other hand, embodiments of the present invention also propose an electronic device that may include the aforementioned chip. This electronic device may be a mobile phone, tablet computer, wearable device, in-vehicle device, laptop computer, super mobile personal computer, netbook, or a dedicated camera (e.g., SLR camera, point-and-shoot camera), etc.

[0072] like Figure 8 As shown, according to an embodiment of this application, a block diagram of a SoC (System on Chip) based electronic device 800 is illustrated. Figure 8 In the diagram, similar components share the same reference numerals. Additionally, dashed boxes are an optional feature for more advanced SoCs. Figure 8In this embodiment, electronic device 800 includes: an interconnect unit 850 coupled to processor 815; a system proxy unit 870; a bus controller unit 880; an integrated memory controller unit 840; a group or one or more coprocessors 820, which may include integrated graphics logic, an image processor, an audio processor, and a video processor; a static random access memory (SRAM) unit 830; and a direct memory access (DMA) unit 860. In one embodiment, coprocessor 820 includes a dedicated processor, such as, for example, a network or communication processor, a compression engine, a GPGPU, a high-throughput MIC processor, or an embedded processor, etc.

[0073] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

[0074] It should be noted that, in the description of this invention, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. When a component is considered to be "connected" to another component, it can be directly connected to the other component or may have a component centrally located simultaneously.

[0075] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature-based current-limiting protection circuit, characterized in that, The circuit includes a feedback control module, a current sampling module, and a reference signal generation module. The current sampling module is connected to the feedback control module, and the feedback control module is connected to the reference signal generation module. The current sampling module is used to collect the output signal of the circuit to obtain a sampling signal; The reference signal generation module is used to determine a reference signal based on temperature. The reference signal generation module includes a temperature acquisition element, which is one or more transistors. The reference signal generation module also includes a control logic module, multiple comparators, multiple control switches, and multiple current sources. The number of multiple comparators is the same as the number of multiple control switches. The base and collector of the one or more transistors are short-circuited and connected to the inverting input of each of the multiple comparators. The non-inverting input of each of the multiple comparators is connected to a reference voltage, and the reference voltage values ​​connected to the non-inverting inputs of each comparator are different. The output of each comparator is connected to the control logic module. The output of the control logic module is connected to the multiple control switches. Each of the multiple control switches is connected to a corresponding current source among the multiple current sources. The feedback control module is used to compare the reference signal with the sampled signal and adjust the output signal according to the comparison result.

2. The temperature-based current-limiting protection circuit according to claim 1, characterized in that, The output signal is either an output current or an output voltage; The sampling signal is either a sampling current or a sampling voltage; The reference signal is a reference current or a reference voltage; The comparison result is either a current comparison result or a voltage comparison result.

3. The temperature-based current-limiting protection circuit according to claim 2, characterized in that, The reference signal generation module is used to generate a reference signal based on temperature, including: The reference signal generation module is used to generate a temperature reference signal based on the temperature. When the temperature reference signal is less than a first temperature threshold, the reference signal generation module determines the reference signal as the first reference signal. When the temperature reference signal is greater than a first temperature threshold and less than a second temperature threshold, the reference signal generation module determines the reference signal as a second reference signal, wherein the second reference signal is greater than the first reference signal. When the temperature reference signal is greater than the second temperature threshold and less than the third temperature threshold, the reference signal generation module determines the reference signal as the third reference signal, and the third reference signal is greater than the second reference signal. When the temperature reference signal is greater than the third temperature threshold, the reference signal generation module determines the reference signal as a fourth reference signal, and the fourth reference signal is greater than the third reference signal.

4. The temperature-based current-limiting protection circuit according to claim 3, characterized in that, The feedback control module is used to compare the reference signal with the sampled signal and adjust the output signal according to the comparison result, including: The feedback control module is used to compare the reference signal with the sampled signal. When the sampled signal does not reach the reference signal, the feedback control module determines to adjust the output signal according to a first control signal. When the sampled signal reaches the reference signal, the feedback control module determines to adjust the output signal according to a second control signal. The first control signal causes the output signal to be less than a set threshold, and the second control signal causes the output signal to be equal to the set threshold.

5. The temperature-based current-limiting protection circuit according to claim 4, characterized in that, The reference signal generation module is further configured to generate a logic signal based on the reference current source and the second control signal, the logic signal being used to control the reference signal to remain unchanged.

6. The temperature-based current-limiting protection circuit according to claim 5, characterized in that, The temperature acquisition element is used to generate the temperature reference signal, which is positively or negatively correlated with the current temperature.

7. The temperature-based current-limiting protection circuit according to claim 6, characterized in that, The plurality of comparators includes a first comparator, a second comparator, and a third comparator; the plurality of control switches includes a first control switch, a second control switch, and a third control switch; and the plurality of current sources includes a first current source, a second current source, and a third current source; and, The base and collector of one or more transistors are shorted and connected to the inverting input of the first comparator, the second comparator, and the third comparator. The outputs of the first comparator, the second comparator, and the third comparator are connected to the control logic module. The output terminals of the control logic module are respectively connected to the first control switch, the second control switch, and the third control switch. The first control switch is connected to the first current source, the second control switch is connected to the second current source, and the third control switch is connected to the third current source.

8. The temperature-based current-limiting protection circuit according to claim 7, characterized in that, The control logic module includes a low-voltage power supply indication signal, an inverter, a first RS flip-flop, a second RS flip-flop, a third RS flip-flop, a first AND gate, a second AND gate, a first NOR gate, a second NOR gate, and a third NOR gate. The low-voltage power supply indication signal is connected to the input terminal of the inverter, and the output terminal of the inverter is connected to the set terminals of the first RS flip-flop, the second RS flip-flop, and the third RS flip-flop, respectively. The logic signal is connected to the first input terminal of the first NOR gate, the second NOR gate, and the third NOR gate. The output of the first comparator is connected to the reset terminal of the first RS flip-flop and the second input of the first NOR gate; the output of the second comparator is connected to the first input of the first AND gate and the second input of the second NOR gate; and the output of the third comparator is connected to the first input of the second AND gate and the second input of the third NOR gate. The NOT signal of the output of the first RS flip-flop is connected to the second input of the first AND gate, and the NOT signal of the output of the second RS flip-flop is connected to the second input of the second AND gate. The output of the first AND gate is connected to the reset terminal of the second RS flip-flop, and the output of the second AND gate is connected to the reset terminal of the third RS flip-flop.

9. A chip, characterized in that, The chip has a temperature-based current limiting protection circuit as described in any one of claims 1-8.

10. An electronic device, characterized in that, The electronic device includes a chip in which a temperature-based current-limiting protection circuit as described in any one of claims 1-8 is formed.

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