A NTC protection control circuit

Abstract

The utility model discloses an NTC protection control circuit, including a power supply, an MCU, an N-MOS tube, an NPN-type triode, a PNP-type triode, a switch button and an NTC thermistor; the power supply is electrically connected to the S pole of the N-MOS tube, and the D pole of the N-MOS tube is electrically connected to the power input pin of the MCU; the power supply, the switch button, and the base of the NPN-type triode are electrically connected in sequence, the collector of the NPN-type triode is electrically connected to the G pole of the N-MOS tube, and the emitter of the NPN-type triode is grounded; the high-level output pin of the MCU is electrically connected to the base of the NPN-type triode, and the output end of the switch button is electrically connected to the key detection pin of the MCU; the emitter of the PNP-type triode is electrically connected to the base of the NPN-type triode, the base of the PNP-type triode is electrically connected to one end of the NTC thermistor, the other end of the NTC thermistor is grounded, and the collector of the PNP-type triode is grounded. During the normal operation of the speaker, once the temperature is too high, the protection is immediately triggered and the speaker is shut down, thereby protecting the speaker.

Description

Technical Field

[0001] The utility model relates to the technical field of sound box temperature protection circuits, in particular to an NTC protection control circuit. Background Art

[0002] As an audio-visual device, speakers are becoming more and more popular in modern people's life and entertainment. The power supply circuit of the existing speakers will generate heat during operation. If the temperature is too high, it is easy to damage the power supply circuit and speaker components, and even cause a fire accident. Therefore, the speaker circuit in the prior art often has an over-temperature protection function. At present, the temperature protection circuit of the speakers on the market basically relies on a single-chip microcomputer or MCU to control according to the temperature data fed back by the temperature sensor. The circuit is complex, and the circuit controlled by the single-chip microcomputer or MCU is not stable and reliable, which is easy to cause control delays, and the circuit cost is high. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an NTC protection control circuit in view of the deficiencies of the above-mentioned prior art. During the normal operation of the speaker, once the temperature is too high, the protection is immediately triggered and the speaker is shut down, thereby protecting the speaker and preventing the risk of fire. The circuit is simple and the cost is low. It does not rely on a single-chip microcomputer or MCU for control. The stability and reliability of the triggered protection are high, and it is not easy to cause control delays.

[0004] In order to solve the above technical problems, the technical solution of the utility model is: an NTC protection control circuit, including a power supply, an MCU, an N-MOS tube, an NPN-type triode, a PNP-type triode, a switch button and an NTC thermistor; the MCU is provided with a power input pin, a high level output pin and a button detection pin; the power supply is electrically connected to the S pole of the N-MOS tube, and the D pole of the N-MOS tube is electrically connected to the power input pin of the MCU; the power supply, the switch button, and the base of the NPN-type triode are electrically connected in sequence, and the The collector of the NPN transistor is electrically connected to the G pole of the N-MOS tube, and the emitter of the NPN transistor is grounded; the high-level output pin of the MCU is electrically connected to the base of the NPN transistor, and the output end of the switch button is electrically connected to the button detection pin of the MCU; the emitter of the PNP transistor is electrically connected to the base of the NPN transistor, the base of the PNP transistor is electrically connected to one end of the NTC thermistor, the other end of the NTC thermistor is grounded, and the collector of the PNP transistor is grounded.

[0005] Preferably, the power source is a battery.

[0006] Preferably, the NTC protection control circuit further comprises a capacitor, one electrode of the capacitor is electrically connected to the S pole of the N-MOS tube, and the other electrode of the capacitor is grounded.

[0007] Preferably, a first diode and a first resistor are connected in series between the output end of the switch button and the base of the NPN transistor.

[0008] Preferably, a second resistor is connected in series between the collector of the NPN transistor and the G pole of the N-MOS transistor, and a third resistor is connected in series between the S pole and the G pole of the N-MOS transistor.

[0009] Preferably, a second diode and a fourth resistor are connected in series between the high-level output pin of the MCU and the base of the NPN transistor.

[0010] Preferably, a third diode and a fifth resistor are connected in series between the output end of the switch button and the button detection pin of the MCU.

[0011] Preferably, a sixth resistor is connected in series between the base of the PNP transistor and the D pole of the N-MOS transistor.

[0012] The beneficial effect of the utility model is as follows: during the operation of the NTC protection control circuit of the utility model, when the temperature in the speaker is too high, according to the working characteristics of the NTC thermistor, the higher the temperature, the smaller the impedance. At this time, the impedance of the NTC thermistor is very small, and the PNP transistor Q3 starts to conduct, thereby lowering the voltage of the base of the NPN transistor Q2, and the NPN transistor Q2 stops working, so that the N-MOS tube Q1 also stops working, and the MCU has no power, so it shuts down, achieving the purpose of protection. The entire temperature protection process does not rely on the single-chip microcomputer or MCU for control. Once the temperature is too high, the protection is immediately triggered and the shutdown is performed, thereby protecting the speaker and preventing the risk of causing a fire. In addition, the circuit is simple, the cost is low, the stability and reliability of the triggered protection are high, and it is not easy to cause the phenomenon of control delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the NTC protection control circuit diagram. DETAILED DESCRIPTION

[0014] The structural principle and working principle of the utility model are further described in detail below with reference to the accompanying drawings.

[0015] like Figure 1As shown, the utility model is an NTC protection control circuit, characterized in that it includes a power supply, an MCU, an N-MOS tube Q1, an NPN transistor Q2, a PNP transistor Q3, a switch button SW101 and an NTC thermistor; the MCU is provided with a power input pin VCC, a high level output pin PWR_ON_HOLD and a key detection pin MCU_POWER_KEY; the power supply is electrically connected to the S pole of the N-MOS tube Q1, and the D pole of the N-MOS tube Q1 is electrically connected to the power input pin VCC of the MCU; the power supply, the switch button SW101, and the base of the NPN transistor Q2 are electrically connected in sequence, and the The collector of the NPN transistor Q2 is electrically connected to the G pole of the N-MOS transistor Q1, and the emitter of the NPN transistor Q2 is grounded; the high-level output pin PWR_ON_HOLD of the MCU is electrically connected to the base of the NPN transistor Q2, and the output end of the switch button SW101 is electrically connected to the key detection pin MCU_POWER_KEY of the MCU; the emitter of the PNP transistor Q3 is electrically connected to the base of the NPN transistor Q2, the base of the PNP transistor Q3 is electrically connected to one end of the NTC thermistor, the other end of the NTC thermistor is grounded, and the collector of the PNP transistor Q3 is grounded.

[0016] like Figure 1 As shown, the power source of the utility model is a battery BAT, and the battery BAT is used to power the entire speaker.

[0017] like Figure 1 As shown, a first diode D1 and a first resistor R2 are connected in series between the output end of the switch button SW101 of the utility model and the base of the NPN transistor Q2. The first diode D1 and the first resistor R2 are a key power-on circuit for powering on / off. Pressing the switch button SW101 can power on / off.

[0018] like Figure 1 As shown, a third diode D2 and a fifth resistor R3 are connected in series between the output end of the switch button SW101 of the present invention and the button detection pin MCU_POWER_KEY of the MCU. The third diode D2 and the fifth resistor R3 are a shutdown circuit for shutting down the MCU.

[0019] like Figure 1 As shown, a second diode D3 and a fourth resistor R1 are connected in series between the high level output pin PWR_ON_HOLD of the MCU of the present invention and the base of the NPN transistor Q2. The second diode D3 and the fourth resistor R1 are used to lock and keep the power on state after the power is turned on.

[0020] As a preferred embodiment of the utility model, the NTC protection control circuit further includes a capacitor C1, one electrode of the capacitor C1 is electrically connected to the S pole of the N-MOS tube Q1, and the other electrode of the capacitor C1 is grounded. A second resistor R5 is connected in series between the collector of the NPN transistor Q2 and the G pole of the N-MOS tube Q1, and a third resistor R4 is connected in series between the S pole and the G pole of the N-MOS tube Q1. A sixth resistor R6 is connected in series between the base of the PNP transistor Q3 and the D pole of the N-MOS tube Q1.

[0021] The working principle of the utility model is as follows:

[0022] 1. When the switch button SW101 is pressed, the electricity of the battery BAT passes through the switch button SW101 to the first diode D1 and the first resistor R2, controls the NPN transistor Q2 to turn on, passes through the second resistor R5 to the G pole of the N-MOS tube Q1, the N-MOS tube Q1 is turned on, and the current passes from the S pole to the D pole of the N-MOS tube Q1, and then to the power input pin VCC of the MCU. The power input pin VCC of the MCU provides power for the MCU, the MCU is awakened, and the power-on action is realized.

[0023] 2. After the MCU is turned on, the high-level output pin PWR_ON_HOLD of the MCU outputs a high level, which passes through the second diode D3 and the fourth resistor R1 to the base of the NPN transistor Q2, so that the NPN transistor Q2 remains in the on state, thereby maintaining the power-on state. After the MCU's key detection pin MCU_POWER_KEY detection pin detects the power-on signal, the MCU remains powered on.

[0024] 3. When you need to shut down, press the switch button SW101. The button detection pin MCU_POWER_KEY detects a high level for the second time, indicating a shutdown command. The high level output pin PWR_ON_HOLD stops outputting voltage, and the NPN transistor Q2 stops working and is in an open circuit state. The N-MOS tube Q1 also stops working. The MCU has no power and stops working, thus being in a shutdown state.

[0025] 4. When the temperature inside the speaker is too high, according to the working characteristics of the NTC thermistor, the higher the temperature, the smaller the impedance. At this time, the impedance of the NTC thermistor is very small, and the PNP transistor Q3 starts to conduct, thereby lowering the voltage of the base of the NPN transistor Q2. The NPN transistor Q2 stops working, and the N-MOS tube Q1 also stops working. The MCU has no power and is shut down, which serves the purpose of protection.

[0026] 5. When the temperature of the NTC thermistor returns to normal temperature, the impedance becomes smaller, and the PNP transistor Q3 stops working. After long pressing the switch button SW101, it can be turned on normally and continue to work.

[0027] During the operation of the NTC protection control circuit of the utility model, when the temperature in the speaker is too high, according to the working characteristics of the NTC thermistor, the higher the temperature, the smaller the impedance. At this time, the impedance of the NTC thermistor is very small, and the PNP transistor Q3 starts to conduct, thereby lowering the voltage of the base of the NPN transistor Q2, and the NPN transistor Q2 stops working, so that the N-MOS tube Q1 also stops working, and the MCU has no power, so it shuts down to achieve the purpose of protection. The entire temperature protection process does not rely on the single-chip microcomputer or MCU for control. Once the temperature is too high, the protection is immediately triggered and the shutdown is performed, thereby protecting the speaker and preventing the risk of causing a fire. In addition, the circuit is simple, the cost is low, the stability and reliability of the triggering protection are high, and it is not easy to cause the phenomenon of control delay.

[0028] The above is only a preferred embodiment of the present invention. Any slight modification, equivalent changes and modifications made to the above embodiments according to the technical solution of the present invention are within the scope of the technical solution of the present invention.

Claims

1. An NTC protection control circuit, characterized in that: The invention comprises a power supply, an MCU, an N-MOS tube (Q1), an NPN transistor (Q2), a PNP transistor (Q3), a switch button (SW101) and an NTC thermistor; the MCU is provided with a power input pin (VCC), a high level output pin (PWR_ON_HOLD) and a key detection pin (MCU_POWER_KEY); the power supply is electrically connected to the S pole of the N-MOS tube (Q1), and the D pole of the N-MOS tube (Q1) is electrically connected to the power input pin (VCC) of the MCU; the power supply, the switch button (SW101) and the base of the NPN transistor (Q2) are electrically connected in sequence, and the collector of the NPN transistor (Q2) is electrically connected to the collector of the NPN transistor (Q2). The electrode is electrically connected to the G electrode of the N-MOS tube (Q1), and the emitter of the NPN transistor (Q2) is grounded; the high-level output pin (PWR_ON_HOLD) of the MCU is electrically connected to the base of the NPN transistor (Q2), and the output end of the switch button (SW101) is electrically connected to the key detection pin (MCU_POWER_KEY) of the MCU; the emitter of the PNP transistor (Q3) is electrically connected to the base of the NPN transistor (Q2), the base of the PNP transistor (Q3) is electrically connected to one end of an NTC thermistor, the other end of the NTC thermistor is grounded, and the collector of the PNP transistor (Q3) is grounded.

2. The NTC protection control circuit according to claim 1, characterized in that: The power source is a battery (BAT).

3. The NTC protection control circuit according to claim 1, characterized in that: It also includes a capacitor (C1), one electrode of the capacitor (C1) is electrically connected to the S pole of the N-MOS tube (Q1), and the other electrode of the capacitor (C1) is grounded.

4. The NTC protection control circuit according to claim 1, characterized in that: A first diode (D1) and a first resistor (R2) are connected in series between the output end of the switch button (SW101) and the base of the NPN transistor (Q2).

5. The NTC protection control circuit according to claim 1, characterized in that: A second resistor (R5) is connected in series between the collector of the NPN transistor (Q2) and the G pole of the N-MOS transistor (Q1), and a third resistor (R4) is connected in series between the S pole and the G pole of the N-MOS transistor (Q1).

6. The NTC protection control circuit according to claim 1, characterized in that: A second diode (D3) and a fourth resistor (R1) are connected in series between the high-level output pin (PWR_ON_HOLD) of the MCU and the base of the NPN transistor (Q2).

7. The NTC protection control circuit according to claim 1, characterized in that: A third diode (D2) and a fifth resistor (R3) are connected in series between the output end of the switch button (SW101) and the button detection pin (MCU_POWER_KEY) of the MCU.

8. The NTC protection control circuit according to claim 1, characterized in that: A sixth resistor (R6) is connected in series between the base of the PNP transistor (Q3) and the D-pole of the N-MOS transistor (Q1).

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