Direct-current wide-voltage constant-power input external lamp circuit

Abstract

The utility model discloses a direct current wide voltage constant power input external lamp circuit, relates to the emergency lighting lamp field, and comprises a power supply circuit, a boost circuit, a lamp group and a power adjusting circuit, the boost circuit comprises a chip U1, an inductor L1, a diode D1, an MOS tube Q2, a resistor D2, and resistors R5-R6, the power adjusting circuit is connected with the chip U1, the lamp group and the ground, and the power adjusting circuit is connected with the chip U1. One end of the resistor D2 is connected between the cathode of the diode D1 and the lamp set, the other end of the resistor D2 is connected to the HVDD pin of the chip U1, the grid electrode of the MOS tube Q2 is connected to the EXT pin of the chip U1, the drain electrode of the MOS tube Q2 is connected between the inductor L1 and the anode of the diode D1, the source electrode of the MOS tube Q2, the resistor R6 and the resistor R5 are sequentially connected in series, and the resistor R5 is connected between the resistor D2 and the lamp set. And the input power is kept constant in the input voltage range. 3-12V direct current can be provided as an input voltage, the range of the input voltage is large, and an external constant-power lighting function can be realized through an external lamp wire under the condition of batteries of various specifications of the emergency lamp.

Description

Technical Field

[0001] The utility model relates to the field of emergency lights, in particular to a DC wide-voltage constant-power input external lamp circuit. Background Art

[0002] Emergency lighting refers to lighting facilities used only under abnormal conditions, including standby lighting, evacuation lighting, and safety lighting, and is widely used in hotels, shopping malls, hospitals, entertainment venues, commercial offices, and civil buildings.

[0003] The battery specifications of emergency lights are numerous and the voltage is small. However, the applicable input voltage of the external lamp is single, and the DC wide-voltage constant-power external lamp can be well applied uniformly. The external lamp cannot be matched with the rated voltage of the battery of the existing emergency lights for power supply, which is very inconvenient. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a DC wide-voltage constant-power input external lamp circuit to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the utility model adopts the following technical scheme: A DC wide-voltage constant-power input external lamp circuit includes a power supply circuit, a boost circuit, a lamp group, and a power adjustment circuit. The boost circuit includes: chip U1, inductor L1, diode D1, MOS transistor Q2, resistor D2, resistors R5 - R6. The power supply circuit, inductor L1, diode D1, and the lamp group are connected in series in sequence. The power adjustment circuit is connected to chip U1, the lamp group, and ground. One end of resistor D2 is connected between the cathode of diode D1 and the lamp group, and the other end of resistor D2 is connected to the HVDD pin of chip U1. The gate of MOS transistor Q2 is connected to the EXT pin of chip U1. The drain of MOS transistor Q2 is connected between the inductor L1 and the anode of diode D1. The source of MOS transistor Q2, resistor R6, and resistor R5 are connected in series in sequence. Resistor R5 is connected between resistor D2 and the lamp group.

[0006] The resistance value of resistor D2 is 30Ω. Resistor D2 serves as a pre-start resistor. After power-on, resistor D2 is connected to the back end of diode D1, and the power supply circuit is connected to the back end through the resistor to achieve the pre-start effect and provide a start voltage for the boost circuit. Resistors R5 and R6 serve as current-limiting resistors to protect the circuit and achieve overvoltage protection through the 0.7V reference inside chip U1.

[0007] Preferably, the power adjustment circuit includes: a DIP switch SW1, resistors R7 to R9, and resistors R11 to R12. One end of resistor R9 is connected to pins 1 and 2 of the DIP switch SW1, and the other end of resistor R9 is connected to the FB pin of chip U1. One ends of resistor R7 and resistor R8 are both connected to pin 4 of the DIP switch SW1 and the lamp group. One ends of resistor R11 and resistor R12 are both connected to pin 3 of the DIP switch SW1. The other ends of resistor R7, resistor R8, resistor R11, and resistor R12 are all grounded. The DIP switch SW1 adjusts the LED current by toggling the switch paddle to achieve power adjustment.

[0008] Preferably, the power supply circuit includes: a positive input pin VIN+, a negative input pin VIN-, an MOS transistor Q1, and resistors R1 to R2. The gate of the MOS transistor Q1, resistor R2, and the negative input pin VIN- are connected in series in sequence. The drain of the MOS transistor Q1 is connected to the positive input pin VIN+, the source of the MOS transistor Q1 is connected to the inductor L1, resistor R1 is connected between the drain and the source of the MOS transistor Q1, and the negative input pin VIN- is grounded. When the positive and negative wires are connected correctly, the internal diode of the MOS transistor Q1 conducts. When the positive and negative wires are connected reversely, the MOS transistor Q1 cuts off, achieving input reverse connection protection.

[0009] Preferably, the power supply circuit further includes capacitors C1 to C2. One ends of capacitor C1 and capacitor C2 are both connected to the negative input pin VIN-, and the other ends of capacitor C1 and capacitor C2 are both connected between the source of the MOS transistor Q1 and the inductor L1.

[0010] Preferably, the boost circuit further includes a first RC series circuit and a second RC series circuit. The first RC series circuit is connected in parallel with diode D1, and the second RC series circuit is connected in parallel with MOS transistor Q2. The first RC series circuit consists of resistor R3 and capacitor C5, and the second RC series circuit consists of resistor R4 and capacitor C6.

[0011] Preferably, the boost circuit further includes capacitors C7, C9 to C10. One end of capacitor C7 is connected to the HVDD pin of chip U1. One end of capacitor C9 is connected between the cathode of diode D1 and the first RC series circuit. One end of capacitor C10 is connected between the cathode of diode D1 and resistor D2. The other ends of capacitor C7, capacitor C9, and capacitor C10 are all connected to the source of the MOS transistor Q2.

[0012] Preferably, the power supply circuit further includes a power input pin Vin. The other end of capacitor C1, the other end of capacitor C2, and the power input pin Vin are all connected between the source of the MOS transistor Q1 and the inductor L1.

[0013] Preferably, the model of the chip U1 is FP7208.

[0014] Preferably, the boost circuit further includes a capacitor C4 and a resistor R10. The EN pin of the chip U1, the resistor R10, the capacitor C4 and the ground are connected in series in sequence. The VDS pin of the chip U1, the capacitor C4 and the ground are connected in series in sequence.

[0015] Preferably, the boost circuit further includes a capacitor C3, a resistor R10 and a capacitor C8. The COMP pin of the chip U1, the capacitor C3 and the ground are connected in series in sequence. The capacitor C8 is connected between the GND pin and the SS pin of the chip U1.

[0016] The beneficial effects of the present utility model are as follows: The input power remains constant within the input voltage range. It can provide 3~12V DC as the input voltage, and the input voltage range is large. It can realize the external constant power lighting function by connecting an external lamp wire in various specifications of battery scenarios of the emergency lamp. Description of the Drawings

[0017] The drawings further illustrate the present utility model, but the embodiments in the drawings do not constitute any limitation to the present utility model.

[0018] Figure 1 It is a circuit diagram provided by an embodiment of the present utility model. Detailed Embodiments

[0019] The following further details the specific embodiments of the present utility model with reference to the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model.

[0020] When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intermediate element present simultaneously.

[0021] As Figure 1 As shown in [figure reference], a DC wide-voltage constant-power input external lamp circuit provided by an embodiment of the present utility model includes a power supply circuit, a boost circuit, a lamp group and a power adjustment circuit. The boost circuit includes: a chip U1, an inductor L1, a diode D1, a MOS transistor Q2, a resistor D2, and resistors R5~R6. The power supply circuit, the inductor L1, the diode D1 and the lamp group are connected in series in sequence. The power adjustment circuit is connected to the chip U1, the lamp group and the ground. One end of the resistor D2 is connected between the cathode of the diode D1 and the lamp group, and the other end of the resistor D2 is connected to the HVDD pin of the chip U1. The gate of the MOS transistor Q2 is connected to the EXT pin of the chip U1. The drain of the MOS transistor Q2 is connected between the inductor L1 and the anode of the diode D1. The source of the MOS transistor Q2, the resistor R6 and the resistor R5 are connected in series in sequence. The resistor R5 is connected between the resistor D2 and the lamp group.

[0022] The resistance value of resistor D2 is 30 Ω. Resistor D2 serves as a pre-start resistor. After power-on, it is connected to the back end of diode D1 by resistor D2, and the power supply circuit is connected to the back end through the resistor to achieve the pre-start effect and provide a start voltage for the boost circuit. Resistors R5 and R6 serve as current-limiting resistors to protect the circuit, and overvoltage protection is achieved through the 0.7V reference inside chip U1.

[0023] The power adjustment circuit includes: DIP switch SW1, resistors R7~R9, resistors R11~R12. One end of resistor R9 is connected to pins 1 and 2 of DIP switch SW1, and the other end of resistor R9 is connected to the FB pin of chip U1. One ends of resistors R7 and R8 are both connected to pins 4 of DIP switch SW1 and the lamp group. One ends of resistors R11 and R12 are both connected to pin 3 of DIP switch SW1. The other ends of resistors R7, R8, R11, and R12 are all grounded. The DIP switch SW1 adjusts the LED current by toggling the dial to achieve power adjustment. The resistance values of resistors R7, R8, R11, and R12 are all equal.

[0024] The power supply circuit includes: positive input pin VIN+, negative input pin VIN-, MOS transistor Q1, resistors R1~R2. The gate of MOS transistor Q1, resistor R2, and negative input pin VIN- are connected in series in sequence. The drain of MOS transistor Q1 is connected to positive input pin VIN+, the source of MOS transistor Q1 is connected to inductor L1, resistor R1 is connected between the drain and source of MOS transistor Q1, and negative input pin VIN- is grounded. When the positive and negative wiring is normal, the internal diode of MOS transistor Q1 conducts. When the positive and negative wiring is reversed, MOS transistor Q1 is cut off to achieve input reverse connection protection.

[0025] The power supply circuit further includes capacitors C1~C2. One ends of capacitors C1 and C2 are both connected to negative input pin VIN-, and the other ends of capacitors C1 and C2 are both connected between the source of MOS transistor Q1 and inductor L1.

[0026] The boost circuit further includes a first RC series circuit and a second RC series circuit. The first RC series circuit is connected in parallel with diode D1, and the second RC series circuit is connected in parallel with MOS transistor Q2. The first RC series circuit consists of resistor R3 and capacitor C5, and the second RC series circuit consists of resistor R4 and capacitor C6.

[0027] The boost circuit further includes a capacitor C7, capacitors C9 to C10. One end of the capacitor C7 is connected to the HVDD pin of the chip U1. One end of the capacitor C9 is connected between the cathode of the diode D1 and the first RC series circuit. One end of the capacitor C10 is connected between the cathode of the diode D1 and the resistor D2. The other ends of the capacitor C7, the capacitor C9 and the capacitor C10 are all connected to the source electrode of the MOS transistor Q2.

[0028] The power supply circuit further includes a power input pin Vin. The other ends of the capacitor C1, the capacitor C2 and the power input pin Vin are all connected between the source electrode of the MOS transistor Q1 and the inductor L1.

[0029] The model of the chip U1 is FP7208.

[0030] The boost circuit further includes a capacitor C4 and a resistor R10. The EN pin of the chip U1, the resistor R10, the capacitor C4 and the ground are connected in series in sequence. The VDS pin of the chip U1, the capacitor C4 and the ground are connected in series in sequence.

[0031] The boost circuit further includes a capacitor C3, a resistor R10, a capacitor C8. The COMP pin of the chip U1, the capacitor C3 and the ground are connected in series in sequence. The capacitor C8 is connected between the GND pin and the SS pin of the chip U1.

[0032] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brief description, not all possible combinations of the technical features in the above embodiments are described. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these should all be considered within the scope described in this specification.

Claims

1. A DC wide voltage constant power input external lamp circuit, characterized in that: The invention comprises a power supply circuit, a boost circuit, a lamp group and a power regulation circuit. The boost circuit comprises: a chip U1, an inductor L1, a diode D1, a MOS tube Q2, a resistor D2, and resistors R5-R6. The power supply circuit, the inductor L1, the diode D1 and the lamp group are connected in series in sequence. The power regulation circuit connects the chip U1, the lamp group and the ground. One end of the resistor D2 is connected between the cathode of the diode D1 and the lamp group, and the other end of the resistor D2 is connected to the HVDD pin of the chip U1. The gate of the MOS tube Q2 is connected to the EXT pin of the chip U1. The drain of the MOS tube Q2 is connected between the inductor L1 and the anode of the diode D1. The source of the MOS tube Q2, the resistor R6 and the resistor R5 are connected in series in sequence. The resistor R5 is connected between the resistor D2 and the lamp group.

2. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The power regulation circuit includes: a dip switch SW1, resistors R7~R9, and resistors R11~R12, one end of the resistor R9 is connected to pins 1 and 2 of the dip switch SW1, and the other end of the resistor R9 is connected to the FB pin of the chip U1, one end of the resistor R7 and the resistor R8 are both connected to pin 4 of the dip switch SW1 and the lamp group, one end of the resistor R11 and the resistor R12 are both connected to pin 3 of the dip switch SW1, and the other ends of the resistors R7, R8, R11 and R12 are all grounded.

3. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The power supply circuit includes: a positive input pin VIN+, a negative input pin VIN-, a MOS tube Q1, and resistors R1-R2. The gate of the MOS tube Q1, the resistor R2, and the negative input pin VIN- are connected in series in sequence. The drain of the MOS tube Q1 is connected to the positive input pin VIN+, the source of the MOS tube Q1 is connected to the inductor L1, the resistor R1 is connected between the drain and the source of the MOS tube Q1, and the negative input pin VIN- is grounded.

4. The DC wide voltage constant power input external lamp circuit according to claim 3, characterized in that: The power supply circuit further includes capacitors C1-C2. One end of the capacitor C1 and the capacitor C2 are both connected to the negative input pin VIN-, and the other end of the capacitor C1 and the capacitor C2 are both connected between the source of the MOS tube Q1 and the inductor L1.

5. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The boost circuit also includes a first RC series circuit and a second RC series circuit. The first RC series circuit is connected in parallel with the diode D1, and the second RC series circuit is connected in parallel with the MOS tube Q2. The first RC series circuit consists of a resistor R3 and a capacitor C5, and the second RC series circuit consists of a resistor R4 and a capacitor C6.

6. The DC wide voltage constant power input external lamp circuit according to claim 5, characterized in that: The boost circuit also includes a capacitor C7 and capacitors C9-C10, one end of the capacitor C7 is connected to the HVDD pin of the chip U1, one end of the capacitor C9 is connected between the cathode of the diode D1 and the first RC series circuit, one end of the capacitor C10 is connected between the cathode of the diode D1 and the resistor D2, and the other ends of the capacitors C7, C9 and C10 are all connected to the source of the MOS tube Q2.

7. The DC wide voltage constant power input external lamp circuit according to claim 4, characterized in that: The power supply circuit further includes a power input pin Vin. The other end of the capacitor C1, the other end of the capacitor C2 and the power input pin Vin are all connected between the source of the MOS tube Q1 and the inductor L1.

8. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The model of the chip U1 is FP7208.

9. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The boost circuit further includes a capacitor C4 and a resistor R10. The EN pin of the chip U1, the resistor R10, the capacitor C4 and the ground are connected in series in sequence. The VDS pin of the chip U1, the capacitor C4 and the ground are connected in series in sequence.

10. The DC wide voltage constant power input external lamp circuit according to claim 1, characterized in that: The boost circuit further includes a capacitor C3, a resistor R10, and a capacitor C8. The COMP pin of the chip U1, the capacitor C3, and the ground are sequentially connected in series. The capacitor C8 is connected between the GND pin and the SS pin of the chip U1.

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