Boost open circuit protection circuit

Abstract

The utility model provides a boost open circuit protection circuit. The boost open circuit protection circuit is characterized by comprising a rectification part, a boost part and a buck part, the AC input end of the rectification part is connected with commercial power, the DC output end of the rectification part is connected with the input end of the boost part, and the output end of the boost part is connected with the step-down part; the boost part is provided with a sampling resistor and a single-chip microcomputer U1. The sampling resistor is connected between the single-chip microcomputer U1 and the DC output cathode of the rectification part. The single-chip microcomputer U1 compares the voltage collected by the sampling resistor with the reference voltage, if the voltage is larger than the reference voltage, the single-chip microcomputer U1 is dormant, and the boosting part does not carry out boosting processing on the direct current output by the rectifying part.

Description

Technical Field

[0001] The utility model relates to the field of lighting, in particular to a boost open - circuit protection circuit. Background Art

[0002] At present, the open - circuit voltage setting of the rear - stage driving IC in the boost - plus - buck scheme is related to the sampling resistor. When power adjustment is performed, the open - circuit voltage will also change accordingly, thus losing the protection function of the open - circuit voltage. Higher creepage distances are required to meet the requirements of safety regulations. Content of the Utility Model

[0003] The main technical problem to be solved by the utility model is to provide a boost open - circuit protection circuit, which can avoid the situation of open - circuit voltage failure when adjusting power.

[0004] To solve the above - mentioned technical problem, the utility model provides a boost open - circuit protection circuit, including: a rectification part, a boost part and a buck part; the AC input end of the rectification part is connected to the mains, and the DC output end is connected to the input end of the boost part, and the output end of the boost part is connected to the buck part;

[0005] The boost part is provided with a sampling resistor and a single - chip microcomputer U1. The sampling resistor is connected between the single - chip microcomputer U1 and the negative pole of the DC output of the rectification part; the single - chip microcomputer U1 compares the voltage collected by the sampling resistor with the reference voltage. If the voltage is greater than the reference voltage, the single - chip microcomputer U1 goes into sleep mode, and the boost part does not boost the direct current output by the rectification part.

[0006] In a preferred embodiment: the sampling resistor includes resistors R2 and R3. Resistor R2 is connected between pin 4 of the single - chip microcomputer U1 and the negative pole of the DC output, and resistor R3 is in parallel with R2.

[0007] In a preferred embodiment: the buck part includes a single - chip microcomputer U2, and its pin 2 is connected to the negative pole of the DC output through a resistor R11.

[0008] In a preferred embodiment: pins 5, 6, 7, and 8 of the single - chip microcomputer U1 are connected. Pin 8 is connected to the positive pole of the DC output through an inductor T1, and pin 5 is connected to the positive pole of the DC output through the anode of a diode D1; the cathode of diode D1 is connected to the cathode of diode D3, and the anode of diode D3 is connected to the same - name terminal of the inductor T1 and the positive pole of the DC output; diode D3 is in parallel with capacitor C4.

[0009] In a preferred embodiment: The positive pole of the DC output is also connected to the negative pole of the DC output through the capacitor C4, the first step-down network, and the capacitor C5; the positive pole of the DC output is also connected to the negative pole of the DC output through the capacitor C4, the second step-down network, and the capacitor C3; the first step-down network is also connected to pin 1 of the single-chip microcomputer U1, and the second step-down network is also connected to pin 3 of the single-chip microcomputer U1; an electrolytic capacitor EC1 is connected between the output terminal of the boost part and the negative pole of the DC output.

[0010] In a preferred embodiment: The input terminal of the boost part is connected to pin 6 of the single-chip microcomputer U2 through the capacitor C6 and the resistor R14, and pin 6 of the single-chip microcomputer is also connected to the input terminal of the boost part through the diode D2; pin 5 of the single-chip microcomputer U2 is connected to the negative pole of the DC output through the inductor T2 and the capacitor C7; pin 8 and pin 1 of the single-chip microcomputer U2 are connected through the resistor R13, and the resistor R13 is connected in parallel with the resistor R12; pin 4 of the single-chip microcomputer U2 is also connected to the negative pole of the DC output through the resistor R16 and the electrolytic capacitor EC1;

[0011] The output terminal of the boost part is connected to the negative pole of the DC output through the electrolytic capacitor EC2 and the capacitor C7; the electrolytic capacitor EC2 is connected in parallel with the resistor R15.

[0012] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0013] The present invention provides a boost open-circuit protection circuit. By collecting the sampling resistors R2 and R3 of the boost part, the collected voltage is compared with the internal reference of U1. When the voltage is lower than a certain value, it can be determined that the LED of the step-down part is open-circuited. Then, the boost part U1 enters the sleep state and does not perform boosting, so that the voltage between AB will decrease, thus playing the role of open-circuit protection. Description of the Drawings

[0014] Figure 1 It is a circuit diagram of a preferred embodiment of the present invention. Detailed Embodiment

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, terms such as "installation", "provided with", "sheathed / connected", "connection", etc. shall be understood in a broad sense. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection, can be a mechanical connection, can be an electrical connection, can be a direct connection, or can be indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0017] This embodiment provides a boost open-circuit protection circuit, including: a rectification part, a boost part, and a buck part; the AC input end of the rectification part is connected to the mains power, and the DC output end is connected to the input end of the boost part, and the output end of the boost part is connected to the buck part;

[0018] The boost part is provided with a sampling resistor and a single-chip microcomputer U1, and the sampling resistor is connected between the single-chip microcomputer U1 and the negative pole of the DC output of the rectification part; the single-chip microcomputer U1 compares the voltage collected by the sampling resistor with the reference voltage. If the voltage is greater than the reference voltage, the single-chip microcomputer U1 goes into sleep mode, and the boost part does not perform boost processing on the direct current output by the rectification part.

[0019] In this embodiment, the sampling resistor includes resistors R2 and R3. The resistor R2 is connected between the 4th pin of the single-chip microcomputer U1 and the negative pole of the DC output, and the resistor R3 is in parallel with R2.

[0020] The step-down part includes a single-chip microcomputer U2, whose pin 2 is connected to the negative pole of the DC output through a resistor R11. Pins 5, 6, 7, and 8 of the single-chip microcomputer U1 are connected, and pin 8 is connected to the positive pole of the DC output through an inductor T1, and pin 5 is connected to the positive pole of the DC output through the anode of a diode D1; the cathode of the diode D1 is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the same-named terminal of the inductor T1 and the positive pole of the DC output; the diode D3 is connected in parallel with a capacitor C4. The positive pole of the DC output is also connected to the negative pole of the DC output through the capacitor C4, a first step-down network, and a capacitor C5; the positive pole of the DC output is also connected to the negative pole of the DC output through the capacitor C4, a second step-down network, and a capacitor C3; the first step-down network is also connected to pin 1 of the single-chip microcomputer U1, and the second step-down network is also connected to pin 3 of the single-chip microcomputer U1; an electrolytic capacitor EC1 is connected between the output terminal of the boost part and the negative pole of the DC output. The input terminal of the boost part is connected to pin 6 of the single-chip microcomputer U2 through a capacitor C6 and a resistor R14, and pin 6 of the single-chip microcomputer is also connected to the input terminal of the boost part through a diode D2; pin 5 of the single-chip microcomputer U2 is connected to the negative pole of the DC output through an inductor T2 and a capacitor C7; pins 8 and 1 of the single-chip microcomputer U2 are connected through a resistor R13, and the resistor R13 is connected in parallel with a resistor R12; pin 4 of the single-chip microcomputer U2 is also connected to the negative pole of the DC output through a resistor R16 and the electrolytic capacitor EC1; the output terminal of the boost part is connected to the negative pole of the DC output through an electrolytic capacitor EC2 and a capacitor C7; the electrolytic capacitor EC2 is connected in parallel with a resistor R15.

[0021] For the above boost open-circuit protection circuit, the boost part keeps the voltage constant at about 400V, and the open-circuit voltage of the LED is set to a voltage value by R11 in the step-down part. By collecting through the sampling resistors R2 and R3 of the boost part, and comparing the collected voltage with the internal reference of U1, when the voltage is lower than a certain value, it can be judged that the LED in the voltage part (U2) is open-circuited, and then the boost part U1 enters the sleep state without boosting, so that the voltage between AB will decrease, thus playing the role of open-circuit protection.

[0022] The above is only the preferred specific implementation manner of the present invention, and does not limit the patent scope of the present invention. Any technical equivalent transformation made using the content of the specification of the present invention shall fall within the protection scope of the present invention.

Claims

1. A boost open circuit protection circuit, characterized in that include: A rectifier part, a boost part and a buck part; the AC input end of the rectifier part is connected to the mains, the DC output end is connected to the input end of the boost part, and the output end of the boost part is connected to the buck part; The boost part is provided with a sampling resistor and a single-chip microcomputer U1, and the sampling resistor is connected between the single-chip microcomputer U1 and the negative pole of the DC output of the rectifier part; the single-chip microcomputer U1 compares the voltage collected by the sampling resistor with the reference voltage, and if the voltage is greater than the reference voltage, the single-chip microcomputer U1 goes into sleep mode, and the boost part does not perform a voltage boost process on the DC power output by the rectifier part.

2. A boost open circuit protection circuit according to claim 1, characterized in that: The sampling resistor includes resistors R2 and R3. The resistor R2 is connected between the 4th pin of the single chip microcomputer U1 and the negative electrode of the DC output. The resistors R3 and R2 are connected in parallel.

3. The boost open circuit protection circuit according to claim 1, characterized in that: The step-down part includes a single-chip microcomputer U2, and a pin 2 thereof is connected to the negative electrode of the DC output through a resistor R11.

4. The boost open circuit protection circuit according to claim 1, characterized in that: Pins 5, 6, 7, and 8 of the single-chip computer U1 are connected, and pin 8 is connected to the DC output positive electrode through the inductor T1, and pin 5 is connected to the DC output positive electrode through the anode of the diode D1; the cathode of the diode D1 is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the same-named ends of the inductor T1 and the DC output positive electrode; the diode D3 is connected in parallel with the capacitor C4.

5. The boost open circuit protection circuit according to claim 4, characterized in that: The DC output positive electrode is also connected to the DC output negative electrode through the capacitor C4, the first step-down network, and the capacitor C5; the DC output positive electrode is also connected to the DC output negative electrode through the capacitor C4, the second step-down network, and the capacitor C3; the first step-down network is also connected to pin 1 of the microcontroller U1, and the second step-down network is also connected to pin 3 of the microcontroller U1; the electrolytic capacitor EC1 is connected between the output end of the boost part and the DC output negative electrode.

6. A boost open circuit protection circuit according to claim 5, characterized in that: The input end of the boost part is connected to the pin 6 of the single-chip computer U2 through the capacitor C6 and the resistor R14, and the pin 6 of the single-chip computer is also connected to the input end of the boost part through the diode D2; the pin 5 of the single-chip computer U2 is connected to the negative electrode of the DC output through the inductor T2 and the capacitor C7; the pin 8 and the pin 1 of the single-chip computer U2 are connected through the resistor R13, and the resistor R13 and the resistor R12 are connected in parallel; the pin 4 of the single-chip computer U2 is also connected to the negative electrode of the DC output through the resistor R16 and the electrolytic EC1; The output end of the boost part is connected to the DC output negative electrode through the electrolytic capacitor EC2 and the capacitor C7; the electrolytic capacitor EC2 is connected in parallel with the resistor R15.

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