Direct-current power supply conversion integrated circuit

Abstract

The utility model relates to the technical field of integrated circuits, and discloses a direct-current power supply conversion integrated circuit in order to solve the technical problem that the existing direct-current power supply conversion circuit is lack of multiple protection mechanisms, so that the circuit cannot meet the requirements of high efficiency, high stability and high safety. Comprising a soft start circuit, an MOS tube, a comparator, a voltage stabilizing circuit, an RS latch, an error amplifier, an overheat protection circuit, an overvoltage protection circuit and an overcurrent protection circuit, a grid electrode of the MOS tube is connected with an output end of the RS latch, a drain electrode of the MOS tube is used for being connected with a first power supply through an inductor and outputting a second direct-current power supply through a diode D1, and the second direct-current power supply is connected with an output end of the RS latch. The source electrode of the MOS tube is grounded through a current detection resistor, the overcurrent protection circuit comprises a current amplifier, the non-inverting input end and the inverting output end of the current amplifier are connected to the two ends of the current detection resistor, and the output end of the current amplifier is connected with the RS latch. And through over-current, over-voltage and over-heat multi-protection, the stability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, and particularly relates to a DC power conversion integrated circuit. Background Art

[0002] Existing DC power conversion integrated circuits are widely used in various electronic devices. Their main function is to convert the input DC power into the required voltage to supply other components in the circuit. However, in actual applications, existing DC power conversion circuits often have some performance limitations, affecting their working stability and safety.

[0003] In the event of abnormal conditions such as overcurrent, overvoltage or overheating in existing circuits, there is a lack of effective protection mechanisms, resulting in the circuit being easily damaged or presenting safety hazards. Especially in terms of overcurrent protection, there are deficiencies in detection accuracy and response speed, unable to identify abnormal conditions in a timely and accurate manner, leading to the failure of the protection function.

[0004] These limitations of existing circuits affect their applications in high-end and sensitive electronic devices, such as medical devices, precision instruments and communication devices, which require extremely high power stability and reliability. Due to the lack of efficient monitoring and control mechanisms, performance fluctuations in existing power conversion circuits may cause unstable operation of the devices, affecting the overall system performance and user experience.

[0005] Therefore, improving the performance of existing DC power conversion integrated circuits has become an important technical requirement. Especially in terms of safety and stability, more advanced technologies are needed to meet the increasingly stringent market and technical standards. This includes improving circuit design, introducing more efficient materials, and developing new circuit topologies and control strategies to enhance the overall performance and safety of the circuit.

[0006] These problems make it difficult for existing DC power conversion circuits to meet the requirements of modern electronic devices for high efficiency, high stability and high safety. Summary of the Utility Model

[0007] The purpose of the utility model is to provide a DC power conversion integrated circuit to solve the technical problem that existing DC power conversion circuits lack multiple protection mechanisms, resulting in the circuits being unable to meet the requirements for high efficiency, high stability and high safety.

[0008] To achieve the above purpose, the specific technical solution of a DC power conversion integrated circuit of the utility model is as follows:

[0009] A DC power conversion integrated circuit includes a soft start circuit, a MOS transistor Q1, a comparator U3, a voltage stabilization circuit for stepping down the input first DC power supply to provide voltage inside the integrated circuit, an RS latch for providing a clock signal to the comparator U3 and the RS latch, an error amplifier U1 provided with an error amplifier for amplifying a feedback signal, an overheat protection circuit, an overvoltage protection circuit, and an overcurrent protection circuit for providing a stop protection signal to the RS latch. The gate of the MOS transistor Q1 is connected to the output terminal of the RS latch. The drain of the MOS transistor Q1 is used to connect to the first power supply through an inductor L1 and is used to output a second DC power supply through a diode D1. The source of the MOS transistor Q1 is grounded through a current detection resistor R1. The overcurrent protection circuit includes a current amplifier U4. The non-inverting input terminal and the inverting output terminal of the current amplifier U4 are respectively connected to both ends of the current detection resistor R1. The output terminal of the current amplifier U4 is connected to the RS latch.

[0010] The soft start circuit controls the voltage rising speed during power startup to avoid current surges from impacting the circuit. The MOS transistor Q1 is controlled to conduct and turn off through the clock signal output by the RS latch, effectively managing the switching frequency of the circuit, improving the efficiency of power conversion. At the same time, the comparator U3 monitors voltage changes to ensure that the conversion circuit operates stably within the set parameter range and prevent voltage fluctuations from having a negative impact on circuit components.

[0011] The voltage stabilization circuit can stably output the input first DC power supply and provide a suitable operating voltage for the internal circuit. The error amplifier U1 can amplify the feedback signal to achieve precise regulation of the output voltage, ensuring stability during the power conversion process. Thus, the circuit can quickly respond to load changes and improve the accuracy and reliability of power supply.

[0012] In the overcurrent protection circuit, by monitoring the source current of the MOS transistor Q1 (achieved through the current detection resistor R1), once the current exceeds the set value, the current amplifier U4 will transmit the signal to the RS latch to control the MOS transistor Q1 to quickly stop working, thereby effectively preventing excessive current from damaging the circuit or components. This design can promptly respond to abnormal current and enhance the safety and stability of the circuit.

[0013] Furthermore, the overvoltage protection circuit includes an operational amplifier U9. The inverting output terminal of the operational amplifier U9 is provided with a reference voltage circuit for providing a reference voltage. The non-inverting input terminal of the operational amplifier U9 is connected to a voltage dividing circuit for detecting the output voltage. The output terminal of the operational amplifier U9 is connected to the RS latch through a diode D5.

[0014] The operational amplifier U9 monitors the output voltage through the reference voltage and the voltage division circuit to ensure that it does not exceed the set protection value. Once overvoltage is detected, the operational amplifier U9 outputs a high level, which is transmitted to the RS latch through the diode D5, causing the MOS transistor Q1 to turn off. This design ensures that the circuit can protect components in a timely manner when the voltage is too high, avoiding irreversible damage to the entire system caused by voltage increase and increasing the reliability of the power conversion circuit.

[0015] Further, the overheat protection circuit includes a triode Q2, and a series-connected resistor R11 and a thermistor R12. The upper end of the thermistor R12 is connected to the voltage stabilization circuit, the lower end of the resistor R11 is grounded, the common node of the resistor R11 and the thermistor R12 is connected to the base of the triode Q2, the emitter of the triode Q2 is grounded, and the collector input of the triode Q2 has a reference voltage provided by the voltage stabilization circuit.

[0016] The thermistor R12 detects the temperature change inside the circuit. Once the temperature rises beyond the safe range, the change in the resistance value of the thermistor R12 will trigger the conduction of the triode Q2, and then control the shutdown operation of the integrated circuit through the reference voltage to protect the circuit from overheat damage. It effectively responds to abnormal temperature conditions and enhances the durability and safety of the circuit.

[0017] A DC power conversion integrated circuit provided by the present utility model has the following advantages:

[0018] The DC power conversion integrated circuit of the present utility model can effectively convert the input voltage and stably output it by integrating a soft start circuit, a MOS transistor Q1, a comparator U3, a voltage stabilization circuit, an RS latch RS1, and an error amplifier U1. Especially when the circuit starts up, the soft start circuit can avoid damage to the circuit caused by current impact, enhancing the stability and service life of the system. At the same time, the built-in overheat protection, overvoltage protection, and overcurrent protection mechanisms in the circuit can respond quickly in case of circuit abnormalities, and achieve real-time monitoring and feedback through detection and amplification devices such as a current amplifier U4, an operational amplifier U9, and a triode Q2, etc., ensuring that the circuit stops working quickly under overload or abnormal temperature conditions, preventing circuit damage or potential safety hazards. This circuit design effectively improves the efficiency, stability, and safety of the overall system, meets the requirements of modern electronic devices for high-performance and high-safety power management, solves the problem of insufficient protection mechanisms in existing power conversion circuits, and enhances the reliability and use safety of the device. Description of the Drawings

[0019] Figure 1 It is a simplified internal and external diagram of the DC power conversion integrated circuit provided by the present utility model;

[0020] Figure 2 It is a structural diagram of the overvoltage protection circuit provided by the present utility model;

[0021] Figure 3 The structural diagram of the overheat protection circuit provided by the present utility model.

[0022] In the figure: U1, error amplifier; U2, comparator; U3, oscillator; U4, current amplifier; U9, operational amplifier; Q1, MOS transistor; Q2, triode; RS1, RS latch; R1, current detection resistor; L1, inductor. Specific embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0024] Refer to Figure 1 , the present utility model provides a DC power conversion integrated circuit for converting and outputting a DC power supply voltage. The figure shows a simplified internal circuit structure diagram of the integrated circuit, including MOS transistor Q1, error amplifier U1, comparator U2, oscillator U3, current amplifier U4, and RS latch RS1. A DC power conversion integrated circuit includes a soft start circuit, MOS transistor Q1, comparator U3, a voltage stabilization circuit for stepping down the input first DC power supply and providing voltage to the inside of the integrated circuit, an RS latch RS1 for providing a clock signal to comparator U3 and RS latch RS1, an error amplifier U1 provided with a feedback signal amplification function, an overheat protection circuit, an overvoltage protection circuit, and an overcurrent protection circuit for providing a stop protection signal to RS latch RS1. The gate of MOS transistor Q1 is connected to the output terminal of RS latch RS1. The drain of MOS transistor Q1 is used to connect to the first power supply through inductor L1 and is used to output a second DC power supply through diode D1. The source of MOS transistor Q1 is grounded through current detection resistor R1. The overcurrent protection circuit includes current amplifier U4. The non-inverting input terminal and the inverting output terminal of current amplifier U4 are respectively connected to both ends of current detection resistor R1. The output terminal of current amplifier U4 is connected to RS latch RS1.

[0025] Among them, the VIN terminal is the power input terminal for accessing an external DC power supply. The voltage stabilization circuit provides a multi-channel stable voltage source for the internal circuit because the external input voltage (VIN) may vary within a relatively wide range. Therefore, through the internal voltage stabilization circuit as a voltage regulator, a stable working voltage is provided for the internal sensitive circuits to ensure that internal modules of the integrated circuit such as error amplifiers and comparators can work reliably.

[0026] The EN terminal is the enable terminal. The EN pin is used to control the turning on and off of the integrated circuit. When the EN pin is at a low level, the integrated circuit is turned off; when it is at a high level, the integrated circuit starts up.

[0027] The SW terminal is the switch terminal of the entire integrated circuit, connected to the drain of the internal MOS transistor Q1, responsible for switching the inductor current and controlling the boost process. The SW terminal is connected to the external inductor L1 and diode D1 to output the boosted voltage. The switching action of the MOS transistor Q1 generates a voltage conversion effect on the external inductor L1, thereby boosting to the target output voltage.

[0028] The FB terminal is the feedback terminal, used to detect the output voltage. The output voltage is fed back to the FB terminal through an external resistor voltage divider circuit composed of resistor R2 and resistor R3. The internal error amplifier compares the feedback voltage with the reference voltage of DC1. By adjusting the error signal, EA will adjust the PWM control signal to regulate the output voltage to reach the desired stable value.

[0029] The comparator U2 compares the error signal output by the error amplifier U1 with the internal oscillator waveform, thereby generating a PWM signal. This signal is used to control the on and off times of the internal power MOS transistor Q1 to achieve the regulation of the output voltage.

[0030] The oscillator U3 generates a triangular wave with a fixed frequency, such as a frequency of 400 kHz, which is used as the time-base signal for the PWM modulator to control the switching frequency and duty cycle of the internal MOS transistor Q1.

[0031] The current amplifier Q4 is the core part of the overcurrent protection circuit, used to monitor the output current. When the output current exceeds the set threshold, the protection function is activated, turning off the MOS transistor Q1 to prevent excessive current from damaging the integrated circuit.

[0032] The overvoltage protection circuit is used to monitor the output voltage. When it detects that the output voltage exceeds the safe range, the overvoltage protection circuit will trigger the protection mechanism to turn off the switch and protect the load and the integrated circuit.

[0033] The overheat protection circuit. When the internal temperature of the integrated circuit exceeds the safe operating range, the overheat protection circuit will turn off the power MOS transistor Q1 to prevent damage to the integrated circuit and ensure the safety of the system.

[0034] The RS latch RS1 is used to control the switching state of the power MOS transistor Q1 to ensure the synchronization and stability of the switch. The RS latch RS1 determines the on and off of the MOS transistor Q1 based on the comparator signal and the input state of the protection circuit (such as overvoltage, overheat, and overcurrent protection).

[0035] The oscillator U3 provides a clock signal to the RS latch RS1 to control its operation. When the clock signal is at a high level, the RS latch RS1 enters the storage mode and does not respond to the input signal at this time. At the same time, when both the set signal and the reset signal are at a low level, the RS latch RS1 also remains in the storage state.

[0036] The soft-start circuit prevents excessive current during startup by slowly increasing the output voltage, avoiding impact on the system and load.

[0037] The under-voltage lockout circuit is used to monitor the input voltage. When the input voltage is lower than the set threshold, the integrated circuit will lock up and not work, preventing unstable output caused by insufficient input voltage.

[0038] The soft-start circuit, over-current protection circuit, over-voltage protection circuit, overheat protection circuit, etc. ensure the safety and stability of the integrated protection circuit under various operating conditions.

[0039] Through the combination of the above methods, the input voltage can be increased to the required stable output voltage, which is applicable to various boost applications.

[0040] See Figure 2 , the over-voltage protection circuit includes an operational amplifier U9. A reference voltage circuit for providing a reference voltage is provided at the inverting output terminal of the operational amplifier U9. A voltage-dividing circuit for detecting the output voltage is connected to the non-inverting input terminal of the operational amplifier U9. The output terminal of the operational amplifier U9 is connected to the RS latch RS1 through a diode D5.

[0041] The reference voltage circuit includes a zener diode D4. The anode of the zener diode D4 is grounded. The cathode of the zener diode D4 is connected to the cathode of a diode D3 through a resistor R4. The anode of the diode D3 is connected to the output terminal DC2 of the voltage regulation circuit. The cathode of the zener diode D4 is connected to the cathode of the operational amplifier U9. A capacitor C1 is connected in parallel with the zener diode D4. The zener diode D4 generates a reference voltage signal and inputs it to the inverting input terminal of the operational amplifier U9.

[0042] The voltage-dividing circuit includes a series-connected resistor R6 and resistor R7. The second terminal of the resistor R7 is grounded. The first terminal of the resistor R7 is connected to the second terminal of the resistor R6. The first terminal of the resistor R6 is connected to the cathode of a diode D7. The anode of the diode D7 is connected to the SW terminal. The common node of the resistor R6 and resistor R7 is connected to the non-inverting input terminal of the operational amplifier U9. The output terminal of the operational amplifier U9 is respectively connected to the non-inverting input terminal of the operational amplifier U9 through a resistor R8 and a diode D6. The resistor R6 and resistor R7 are used to detect the output voltage and input the detected voltage value to the non-inverting input terminal of the operational amplifier U9.

[0043] When the output voltage does not reach the overvoltage protection point, the voltage at the non-inverting input terminal is less than the voltage at the inverting input terminal. The operational amplifier U9 outputs a low level, and the output is normal.

[0044] When the output voltage rises to the set detection point voltage, the divided voltages detected by resistor R6 and resistor R7 are fed into the non-inverting input terminal. At this time, the voltage at the non-inverting input terminal is greater than the voltage at the inverting input terminal. The operational amplifier U9 outputs a high level, blocking the PWM signal of the control integrated circuit, and the output voltage of the integrated circuit is zero.

[0045] Through the cooperation of the operational amplifier U9 and the voltage dividing circuit, when the output voltage does not reach the set overvoltage protection point, the operational amplifier maintains a low-level output and the circuit works normally; when the output voltage exceeds the set value, the voltage dividing circuit detects the voltage increase, and the operational amplifier U9 switches to a high-level output, triggering the diode D5 to block the PWM control signal, and the MOS transistor turns off, thus preventing the output voltage from rising further and protecting the system or load from damage due to overvoltage. At the same time, the zener diode D4 generates a stable reference voltage to ensure the precise response of the protection circuit. This circuit design has the advantages of rapid response, simple structure, and reliable protection, can effectively prevent circuit damage caused by overvoltage, and improves the safety and stability of the power conversion circuit.

[0046] See Figure 3 , the overheat protection circuit includes a triode Q2, and a series of resistor R11 and a thermistor R12. The upper end of the thermistor R12 is connected to the voltage stabilizing circuit, the lower end of the resistor R11 is grounded, the common node of the resistor R11 and the thermistor R12 is connected to the base of the triode Q2, the emitter of the triode Q2 is grounded, the collector of the triode Q2 inputs a reference voltage provided by the voltage stabilizing circuit through a pull-up resistor R13, and the collector of the triode Q2 is connected to the RS latch RS1 through a resistor R14.

[0047] The thermistor R12 is a negative temperature coefficient thermistor. It mainly detects the temperature change through the thermistor R12 and controls the conduction or cut-off of the triode Q2 to achieve the overheat protection function of the circuit. The specific working principle is as follows:

[0048] When the circuit is working normally, the resistance value of the thermistor R12 is relatively large, resulting in a relatively low base voltage of the triode Q2, which is lower than its conduction voltage. Therefore, Q2 is in the cut-off state. In this case, the collector of Q2 outputs a high-level signal (i.e., the reference voltage remains unchanged), indicating that the circuit is working normally and there is no overheat situation.

[0049] As the circuit temperature rises, the resistance value of the thermistor R12 decreases with the increase in temperature. After the resistance value of the thermistor decreases, the voltage division circuit composed of the resistor R11 will increase the base voltage of the triode Q2. When the temperature exceeds the set value, the base voltage rises to the conduction voltage of the triode, and Q2 starts to conduct. After Q2 conducts, its collector voltage rapidly drops to near ground potential, thereby outputting a low-level signal, triggering the protection mechanism, shutting down or restricting the operation of the circuit, and preventing overheating damage.

[0050] This overheat protection circuit uses the sensitive response of the thermistor R12 to temperature changes, combined with the conduction control of the triode Q2, to input a switching signal to the RS latch RS1, realizing automatic overheat protection for the integrated circuit.

[0051] Implementing the present utility model provides the beneficial effects brought by a DC power conversion integrated circuit as follows:

[0052] The DC power conversion integrated circuit provided by the present utility model has multiple protection mechanisms to ensure the safety and stability of the circuit. Especially in terms of overheat protection, by setting up an overheat protection circuit composed of the thermistor R12 and the triode Q2, using the negative temperature characteristic of the thermistor, it can detect the temperature change of the circuit in a timely manner. When the temperature is too high, the resistance value of the thermistor drops, driving the triode Q2 to conduct, outputting a low-level signal, turning off the MOS tube Q1 through the RS latch RS1, and then shutting down the entire circuit to avoid damage caused by overheating. This solution effectively protects the circuit without affecting its normal operation. When the temperature returns to normal, the circuit can also restart quickly. In addition, multiple functional modules such as the soft start circuit, overcurrent protection circuit, and overvoltage protection circuit in the integrated circuit work together to provide a stable voltage output and ensure the safety of the system under various conditions.

[0053] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A DC power conversion integrated circuit, comprising a soft start circuit, a MOS transistor (Q1), a comparator (U2), a voltage regulator circuit for stepping down the input first DC power supply to provide voltage inside the integrated circuit, an RS latch (RS1) for providing a clock signal to the comparator (U2) and the RS latch (RS1), and an error amplifier (U1) provided with means for amplifying a feedback signal, characterized in that An overheat protection circuit, an overvoltage protection circuit, and an overcurrent protection circuit are provided for supplying a stop protection signal to an RS latch (RS1). The gate of the MOS transistor (Q1) is connected to the output terminal of the RS latch (RS1). The drain of the MOS transistor (Q1) is used to be connected to a first power supply through an inductor (L1), and is used to output a second DC power supply through a diode D1. The source of the MOS transistor (Q1) is grounded through a current detection resistor (R1). The overcurrent protection circuit includes a current amplifier (U4). The non-inverting input terminal and the inverting output terminal of the current amplifier (U4) are respectively connected to both ends of the current detection resistor (R1). The output terminal of the current amplifier (U4) is connected to the RS latch (RS1).

2. The DC power conversion integrated circuit according to claim 1, wherein The overvoltage protection circuit includes an operational amplifier (U9). A reference voltage circuit for providing a reference voltage is provided at the inverting output terminal of the operational amplifier (U9). A voltage dividing circuit for detecting the output voltage is connected to the non-inverting input terminal of the operational amplifier (U9). The output terminal of the operational amplifier (U9) is connected to the RS latch (RS1) through a diode D5.

3. The DC power conversion integrated circuit according to claim 2, characterized in that, The overheat protection circuit includes a triode (Q2), and a resistor R11 and a thermistor R12 connected in series. The upper end of the thermistor R12 is connected to a voltage stabilizing circuit. The lower end of the resistor R11 is grounded. The common node of the resistor R11 and the thermistor R12 is connected to the base of the triode (Q2). The emitter of the triode (Q2) is grounded. The collector of the triode (Q2) inputs a reference voltage provided by the voltage stabilizing circuit.

Images