A control unit and a circuit applied to a street lamp

Abstract

The utility model discloses a control unit and be applied to circuit of street lamp belongs to lighting equipment technical field, including voltage control ring, current control ring and drive signal generating module, and the output of voltage control ring is connected with the cathode of first diode, and the output of current control ring is connected with the cathode of second diode, and the anode of first diode and the anode of second diode are parallelly connected and are connected with drive signal generating module in series, voltage control ring first input receives reference voltage signal, and voltage control ring second input receives sampling voltage signal, current control ring first input receives reference current signal, and current control ring second input receives sampling current signal, the circuit of the utility model discloses this be applied to street lamp, improves the safety and reliability of circuit structure while the structure is simplified, and good balance is obtained between battery life and charging speed under the condition of guaranteeing LED load work stable.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of lighting equipment, and especially relates to a control unit and a circuit applied to a street lamp. BACKGROUND

[0002] LED is widely used in lighting, display and other fields due to its advantages of high efficiency, long service life and the like. With the development of technology, the brightness and efficiency of LED are continuously improved.

[0003] Generally, LED street lamps are installed on roads in urban areas and the like, so that people can safely pass through at night. The ordinary solar street lamp is charged by a solar panel during the day, and the battery is discharged to light the street lamp at night. However, the single-function solar street lamp is often affected by the weather, resulting in a low lighting rate. In addition, the battery used in the solar street lamp is connected in series by multiple battery cores, and generally has a battery protection board. The failure of the protection board can easily cause the battery to catch fire.

[0004] Therefore, there is an urgent need for a new circuit structure applied to an LED street lamp with a storage battery, which is charged by power supply and solar energy to ensure the lighting rate. In addition, the protection board can be removed to avoid damage to the battery caused by the failure of the protection board, thereby fully ensuring the safety of the battery. At the same time, the battery energy storage principle is utilized, the battery is charged by the power supply during off-peak hours; the battery is discharged during peak hours, and the power supply does not participate in power supply, thereby balancing the power grid load. SUMMARY

[0005] The utility model aims at providing a control unit and a circuit applied to a street lamp, to achieve the above-mentioned purpose, the utility model technical scheme is:

[0006] A control unit, comprising a voltage control loop, a current control loop and a drive signal generation module, the output end of the voltage control loop is connected with the cathode of a first diode, the output end of the current control loop is connected with the cathode of a second diode, the anode of the first diode and the anode of the second diode are connected in parallel and then connected in series with the drive signal generation module;

[0007] The first input end of the voltage control loop receives a reference voltage signal, and the second input end of the voltage control loop receives a sampling voltage signal;

[0008] The first input end of the current control loop receives a reference current signal, and the second input end of the current control loop receives a sampling current signal.

[0009] Further, the voltage control loop comprises,

[0010] a first resistor, the first end of which is connected with the reference voltage signal;

[0011] a first switch, the first end of which is connected with the second end of the first resistor, and the second end of which is grounded.

[0012] a second resistor, a first end of which is connected to the third end of the first switch, and a second end of which is connected to a bias voltage;

[0013] a third resistor, a first end of which is connected to the first end of the first switch, and a second end of which is connected to ground;

[0014] a fourth resistor, a first end of which is connected to the third end of the first switch;

[0015] a first comparator, a positive input end of which is connected to the second end of the fourth resistor, and a negative input end and an output end of which are connected together;

[0016] a first capacitor, a first end of which is connected to the positive input end of the first comparator, and a second end of which is connected to ground;

[0017] a fifth resistor, a first end of which is connected to the output end of the first comparator;

[0018] a second comparator, a positive input end of which is connected to the second end of the fifth resistor, and a negative input end of which is connected to the sampling voltage signal;

[0019] a second capacitor and a seventh resistor, which are connected in series between the negative input end and the output end of the second comparator;

[0020] a sixth resistor, a first end of which is connected to ground, and a second end of which is connected to the negative input end of the second comparator;

[0021] a first diode, a cathode of which is connected to the output end of the second comparator.

[0022] Further, the current control loop comprises,

[0023] an eighth resistor, a first end of which is connected to the reference current signal;

[0024] a second switch, a first end of which is connected to the second end of the eighth resistor, and a second end of which is connected to ground;

[0025] a ninth resistor, a first end of which is connected to the third end of the second switch, and a second end of which is connected to a bias voltage;

[0026] a tenth resistor, a first end of which is connected to the first end of the second switch, and a second end of which is connected to ground;

[0027] an eleventh resistor, a first end of which is connected to the third end of the second switch;

[0028] a third comparator, a positive input end of which is connected to the second end of the eleventh resistor, and a negative input end and an output end of which are connected together;

[0029] a third capacitor, a first end of which is connected to the positive input end of the third comparator, and a second end of which is connected to ground;

[0030] a twelfth resistor having a first end connected to an output of the third comparator;

[0031] a fourth comparator having a positive input connected to a second end of the twelfth resistor;

[0032] a fourth capacitor and a fourteenth resistor connected in series between a negative input and an output of the fourth comparator;

[0033] a thirteenth resistor having a first end connected to the sampled current signal and a second end connected to the negative input of the fourth comparator;

[0034] a second diode having a cathode connected to the output of the fourth comparator.

[0035] A circuit applied to a street lamp, comprising,

[0036] an AC / DC conversion module having an input connected to an AC power supply and an output connected in parallel to a DC bus, the bus voltage;

[0037] a first DC / DC conversion module having an input connected to the output of the AC / DC conversion module and an output connected in parallel to a battery;

[0038] a second DC / DC conversion module having an input connected to the output of the AC / DC conversion module and an output connected in parallel to an LED load;

[0039] a control unit comprising a voltage control loop, a current control loop and a drive signal generation module, the voltage control loop having an output connected to a cathode of a first diode, the current control loop having an output connected to a cathode of a second diode, the anode of the first diode and the anode of the second diode being connected in parallel and in series with the drive signal generation module;

[0040] the voltage control loop having a first input receiving a reference voltage signal and a second input receiving a sampled voltage signal of the DC bus;

[0041] the current control loop having a first input receiving a reference current signal and a second input receiving a sampled current signal of the DC bus.

[0042] Further, the AC / DC conversion module comprises a third diode, a fourth diode, a fifth diode and a sixth diode, the cathode of the third diode is connected to the cathode of the fourth diode, the anode of the fourth diode is connected to the cathode of the sixth diode, the anode of the sixth diode is connected to the anode of the fifth diode, the cathode of the fifth diode is connected to the anode of the third diode, the first end of the AC power is connected to the anode of the third diode, and the second end of the AC power is connected to the anode of the fourth diode.

[0043] Further, the AC / DC conversion module further comprises a fifth capacitor, one end of which is connected to the cathode of the fourth diode, and the other end of which is connected to the anode of the fifth diode,

[0044] a first transformer, the first end of the primary winding of which is connected to the cathode of the fourth diode, and the second end of the secondary winding of which is connected to the secondary ground,

[0045] a third switch tube, the first end of which is connected to the second end of the primary winding of the first transformer,

[0046] a fifteenth resistor, one end of which is connected to the second end of the third switch tube, and the other end of which is connected to the primary ground,

[0047] a fourth switch tube, the second end of which is connected to the first end of the secondary winding of the first transformer,

[0048] a sixth capacitor, the first end of which is connected to the first end of the fourth switch tube, and the second end of which is connected to the second end of the secondary winding of the first transformer, and the two ends of the sixth capacitor are connected to the input end of the first DC-DC conversion module.

[0049] Further, the first DC-DC conversion module comprises a seventh capacitor, which is connected in parallel with the sixth capacitor,

[0050] a fifth switch tube, the first end of which is connected to the first end of the seventh capacitor,

[0051] a sixth switch tube, the first end of which is connected to the second end of the fifth switch tube, and the second end of which is connected to the second end of the seventh capacitor and the negative electrode of the battery,

[0052] a first inductor, the first end of which is connected to the first end of the sixth switch tube, and the second end of which is connected to the positive electrode of the battery,

[0053] an eighth capacitor, the first end of which is connected to the second end of the first inductor, and the second end of which is connected to the second end of the sixth switch tube.

[0054] Further, the second DC-DC conversion module comprises a ninth capacitor, the first end of which is connected to the first end of the fourth switch tube, and the second end of which is connected to the secondary ground,

[0055] a second inductor, a first end of which is connected to a first end of the ninth capacitor,

[0056] a seventh switch tube, a first end of which is connected to a second end of the second inductor, and a second end of which is connected to a second end of the ninth capacitor,

[0057] a seventh diode, an anode of which is connected to the first end of the seventh switch tube, and a cathode of which is connected to a first end of the LED load,

[0058] a tenth capacitor, a first end of which is connected to the cathode of the seventh diode, and a second end of which is connected to the second end of the seventh switch tube,

[0059] a sixteenth resistor, one end of which is connected to the second end of the tenth capacitor, and the other end of which is connected to a second end of the LED load.

[0060] Further, when there is AC input but the LED load is not working, the battery is in a charging mode, the output current of the DC bus is lower than a constant current setting value, the AC / DC conversion module is controlled to work in a constant voltage mode or a constant current mode, and the maximum charging power of the battery is limited;

[0061] When there is AC input and the LED load is working, the battery is not in a charging and discharging mode, the output current of the DC bus is lower than the constant current setting value, the AC / DC conversion module is controlled to work in the constant voltage mode, and the LED load output current is constant;

[0062] When there is AC input and the LED load is working, the battery is in a charging mode, the output current of the DC bus is equal to the constant current setting value, the AC / DC conversion module is controlled to work in a constant current or constant voltage mode, the maximum charging power of the battery is limited, and the LED load output current is constant;

[0063] When there is no AC input but the LED load is working, the battery is in a discharging mode, the AC / DC conversion module stops working, the battery supplies power to the LED load through the first DC / DC conversion module and the second DC / DC conversion module, and the LED load output current is constant.

[0064] The application has the advantages that the application of the circuit for LED driving has a simple structure and improves the reliability of the circuit structure and prolongs the overall service life of the LED. In the case of ensuring the stable working power of the LED load, a good balance between the battery life and the charging speed is achieved.

[0065] In order to make the above features and advantages of the application more obvious and easy to understand, the following embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 The utility model relates to a control unit and a circuit structure block diagram applied to street lamp.

[0067] Figure 2 The utility model relates to a control unit and a circuit first specific embodiment applied to street lamp.

[0068] Figure 3 The utility model relates to Figure 2 The utility model relates to a circuit structure diagram of control unit.

[0069] In the drawings, similar reference numerals refer to identical drawing elements.

[0070] Drawing mark explanation:

[0071] 11, 21 - AC / DC conversion module; 12, 22 - first DC / DC conversion module; 13, 23 - second DC / DC conversion module; 24 - control unit; 241 - voltage control loop; 242 - current control loop; 243 - drive signal generation module. DETAILED DESCRIPTION

[0072] To make the purpose and technical scheme of the utility model embodiment clearer, the technical scheme of the utility model embodiment will be described clearly and completely below in combination with the drawings of the utility model embodiment. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiment. Based on the described embodiment of the utility model, all other embodiments obtained by the ordinary skill in the art without creative labor belong to the protection scope of the utility model.

[0073] Figure 1 The utility model relates to a control unit and a circuit structure block diagram applied to street lamp, including AC / DC conversion module 11, first DC / DC conversion module 12 and second DC / DC conversion module 13, and AC AC / DC conversion module 11 is carried out AC / DC conversion after AC AC and obtains direct current, the output end of AC / DC conversion module 11 exports bus voltage Vbus, the input end of first DC / DC conversion module 12 is connected with the output end of AC / DC conversion module 11, the output end of first DC / DC conversion module 12 is parallel battery BT, the input end of second DC / DC conversion module 13 is connected with the output end of AC / DC conversion module 11, and the output end of second DC / DC conversion module 13 is parallel LED load.

[0074] Further, the first DC / DC conversion module 12 is a bidirectional DC-DC (DC-DC) converter.

[0075] Further, during valley electricity, the alternating current AC is converted into a direct current voltage by the AC / DC conversion module 11 to generate the bus voltage Vbus, which only charges the battery BT via the first DC / DC conversion module 12, or the bus voltage Vbus charges the battery BT via the first DC / DC conversion module 12 and simultaneously supplies power to the LED load via the second DC / DC conversion module 13, or the bus voltage Vbus only supplies power to the LED load via the second DC / DC conversion module 13; during peak electricity, the battery BT discharges to maintain the bus voltage Vbus via the first DC / DC conversion module 12, and the bus voltage Vbus supplies power to the LED load via the second DC / DC conversion module 13, thereby achieving the function of saving electric energy.

[0076] Optionally, whether to turn on the LED load can be selected as needed by the second DC / DC conversion module 13. For example, during valley electricity, the alternating current AC is converted into a direct current voltage by the AC / DC conversion module 11 to generate the bus voltage Vbus, and the second DC / DC conversion module 13 supplies power to the LED load.

[0077] Figure 2 For a specific embodiment of the control unit and the circuit applied to the street lamp of the utility model, the AC / DC conversion module 21, the first DC / DC conversion module 22, the second DC / DC conversion module 23, and the control unit 24 are included, the alternating current AC is converted into a direct current after the AC / DC conversion of the AC / DC conversion module 21, the output end of the AC / DC conversion module 21 outputs the bus voltage Vbus, the input end of the first DC / DC conversion module 12 is connected with the output end of the AC / DC conversion module 11, the output end of the first DC / DC conversion module 12 is connected with the battery BT in parallel, the input end of the second DC / DC conversion module 13 is connected with the output end of the AC / DC conversion module 11, the output end of the second DC / DC conversion module 13 is connected with the LED load in parallel, and the control unit 24 is connected with the AC / DC conversion module and controls the bus voltage and the bus current.

[0078] More specifically, the AC / DC conversion module 21 is a rectification conversion bridge, which includes diode D1, diode D2, diode D3, and diode D4, the cathode of the diode D1 is connected with the cathode of the diode D2, the anode of the diode D2 is connected with the cathode of the diode D4, the anode of the diode D4 is connected with the anode of the diode D3, the cathode of the diode D3 is connected with the anode of the diode D1, the first end of the alternating current AC is connected with the anode of the diode D1, and the second end of the alternating current AC is connected with the anode of the diode D2.

[0079] The AC / DC conversion module 21 further comprises a capacitor C1, a capacitor C2, a switch tube Q1, a switch tube Q2, a resistor Ra and a transformer T1, one end of the capacitor C1 is connected to the cathode of the diode D2, the other end of the capacitor C1 is connected to the anode of the diode D3, the first end of the primary winding of the transformer T1 is connected to the cathode of the diode D2, the second end of the primary winding of the transformer T1 is connected to the drain of the switch tube Q1, one end of the resistor Ra is connected to the source of the switch tube Q1, the other end of the resistor Ra is connected to the ground terminal PGND, the first end of the secondary winding of the transformer T1 is connected to the source of the switch tube Q2, the first end of the capacitor C2 is connected to the drain of the switch tube Q2, the second end of the capacitor C2 is connected to the second end of the secondary winding of the transformer T1, the second end of the secondary winding of the transformer T1 is connected to the ground terminal SGND, and the two ends of the capacitor C2 are connected to the input end of the first DC / DC conversion module 22.

[0080] Optionally, the capacitor C2 comprises a plurality of capacitors connected in parallel.

[0081] Optionally, the switch tube Q1 and the switch tube Q2 are N-channel MOSFETs.

[0082] The first DC / DC conversion module 22 is of a bidirectional BUCK-BOOST topology, but the present application is not limited thereto, and other topologies having bidirectional DC-DC conversion functions can also be used, and comprises a capacitor C3, a capacitor C4, a switch tube Q3, a switch tube Q4 and an inductor L1, the capacitor C3 is connected in parallel with the capacitor C2, the drain of the switch tube Q3 is connected to the first end of the capacitor C3, the source of the switch tube Q3 is connected to the drain of the switch tube Q4, the source of the switch tube Q4 is connected to the second end of the capacitor C3, the first end of the inductor L1 is connected to the drain of the switch tube Q4, the first end of the capacitor C4 is connected to the second end of the inductor L1, the second end of the capacitor C4 is connected to the source of the switch tube Q4, the positive electrode of the battery BT is connected to the second end of the inductor L1, and the negative electrode of the battery BT is connected to the source of the switch tube Q4.

[0083] Optionally, the switch tube Q3 and the switch tube Q4 are N-channel MOSFETs.

[0084] The second direct current / direct current conversion module 23 is a BOOST topological structure, but the utility model is not limited to this, other topological structures with direct current-direct current conversion functions can be used, including a capacitor C5, a capacitor C6, an inductor L2, a switch tube Q5, a diode D5 and a resistor Rb, the first end of the capacitor C5 is connected with the drain electrode of the switch tube Q2, the second end of the capacitor C5 is connected with the secondary side ground terminal SGND, the first end of the inductor L2 is connected with the first end of the capacitor C5, the second end of the inductor L2 is connected with the drain electrode of the switch tube Q5, the source electrode of the switch tube Q5 is connected with the second end of the capacitor C5, the anode of the diode D5 is connected with the drain electrode of the switch tube Q5, the first end of the capacitor C6 is connected with the cathode of the diode D5, the second end of the capacitor C6 is connected with the source electrode of the switch tube Q5, one end of the resistor Rb is connected with the second end of the capacitor C6, the other end of the resistor Rb is connected with the cathode of the LED, and the anode of the LED is connected with the cathode of the diode D5.

[0085] Further, the switch tube Q5 adopts constant current control.

[0086] Optionally, the switch tube Q5 is an N-channel MOSFET.

[0087] The utility model discloses a first direct current / direct current conversion module 22 connects a single lithium battery, i.e. the battery BT, and the whole becomes a battery pack, and the voltage presented to the outside is the bus voltage Vbus, which is equivalent to a plurality of batteries in series, and the current to the outside is reduced under the same power condition, thereby relieving the large current and low voltage problem of the single lithium battery applied to the LED load.

[0088] Figure 3 It is a circuit structural drawing of a control unit and a circuit control unit applied to a street lamp, and the control unit comprises a voltage control ring 241, a current control ring 242 and a driving signal generation module 243.

[0089] The first input end of the voltage control ring 241 receives a reference voltage signal, and the second input end of the voltage control ring 241 receives a sampling voltage signal.

[0090] The first input end of the current control ring 242 receives a reference current signal, and the second input end of the current control ring 242 receives a sampling current signal.

[0091] More specifically, in the voltage control loop 241, one end of resistor R1 is connected to the reference voltage port (ACVPWM), and the other end is connected to the gate of switch Qv, the source of switch Qv is grounded, the drain of switch Qv is connected to one end of resistor R2, the other end of resistor R2 is connected to a 2.5V bias voltage, one end of resistor R3 is grounded, and the other end is connected to the gate of switch Qv; one end of resistor R4 is connected to the drain of switch Qv, and the other end is connected to the positive input of comparator U1; one end of capacitor Ca is grounded, and the other end is connected to the positive input of comparator; one end of resistor R5 is connected to the output of comparator U1, and the other end is connected to the positive input of comparator U2; the sampling voltage port (VS) is connected to the negative input of comparator U2; capacitor Cb is connected in series with resistor R7, and then connected in parallel as a feedback loop between the output and negative input of the comparator; one end of resistor R6 is grounded, and the other end is connected to the sampling voltage port.

[0092] In the current control loop 242, one end of resistor R8 is connected to the reference current port (ACIPWM), and the other end is connected to the gate of switch Qi, the source of switch Qi is grounded, the drain of switch Qi is connected to one end of resistor R9, the other end of resistor R9 is connected to a 2.5V bias voltage, one end of resistor R10 is grounded, and the other end is connected to the gate of switch Qi; one end of resistor R11 is connected to the drain of switch Qi, and the other end is connected to the positive input of comparator U3; one end of capacitor Cc is grounded, and the other end is connected to the positive input of comparator; one end of resistor R12 is connected to the output of comparator U3, and the other end is connected to the positive input of comparator U4; the sampling current port (Isense) is connected to the negative input of comparator U4; capacitor Cd is connected in series with resistor R14, and then connected in parallel as a feedback loop between the output and negative input of the comparator; one end of resistor R13 is grounded, and the other end is connected to the sampling voltage port.

[0093] The anodes of diodes Dv and Di are connected in parallel as the output signal port FEED of the control unit, the cathode of diode Dv is connected to the output of comparator U2, and the cathode of diode Di is connected to the output of comparator U4.

[0094] The drive signal generation module 243 generates a drive signal for controlling switch Q1 based on the FEED signal.

[0095] The reference voltage signal and the reference current signal are in the form of PWM waves, the reference voltage signal is compared with the sampling voltage signal, the error signal generated by the comparison is output to the FEED output end, the reference current signal is compared with the sampling current signal, the error signal generated by the comparison is also output to the FEED output end, the FEED output end selects the control loop with lower error signal, and inputs the generated signal to the driving signal generation module, so as to adjust the duty cycle of the PWM, control the on time of the switch, and perform constant voltage or constant current control on the external circuit.

[0096] When the bus output current is lower than the reference current signal value, the parallel constant current control is invalid, and the line is maintained at 12.3v by constant voltage control. When the bus output current is higher than the reference current signal value, the parallel constant voltage control is invalid, and the line is maintained at 10A output current by constant current control, and the voltage decreases.

[0097] More specifically, when there is an AC input but the LED load is not working, the battery is in a charging mode, the output current of the DC bus is lower than the constant current setting value, the AC / DC conversion module is controlled to work in a constant voltage mode or a constant current mode, and the maximum charging power of the battery is limited.

[0098] When there is an AC input and the LED load is working, the battery is not in a charging and discharging mode, the output current of the DC bus is lower than the constant current setting value, the AC / DC conversion module is controlled to work in a constant voltage mode, and the LED load output current is constant.

[0099] When there is an AC input and the LED load is working, the battery is in a charging mode, the output current of the DC bus is equal to the constant current setting value, the AC / DC conversion module is controlled to work in a constant current or constant voltage mode, the maximum charging power of the battery is limited, and the LED load output current is constant.

[0100] When there is no AC input but the LED load is working, the battery is in a discharging mode, the AC / DC conversion module stops working, the battery supplies power to the LED load through the first DC / DC conversion module and the second DC / DC conversion module, and the LED load output current is constant.

[0101] The sampling interruption period of the utility model is very long, up to 10 milliseconds, the switching frequency is 10 microseconds, and multiple switching periods are interrupted only once.

[0102] The control unit and the circuit applied to the street lamp have a simple structure and improve the reliability of the circuit structure, and prolong the overall service life of the LED load. Under the condition that the working power of the LED load is stable, a good balance is achieved between the battery life and the charging speed.

[0103] Although the utility model has disclosed as above with examples, it is not used to limit the utility model, anyone with ordinary knowledge in the art can make some changes and decorations without departing from the spirit and scope of the utility model, so the protection scope of the utility model is defined by the appended patent application scope.

Claims

1. A control unit, characterized by The voltage control loop, the output end of which is connected with the cathode of the first diode, the output end of the current control loop is connected with the cathode of the second diode, and the anode of the first diode and the anode of the second diode are connected in parallel and then connected in series with the driving signal generation module; The first input end of the voltage control loop receives a reference voltage signal, and the second input end of the voltage control loop receives a sampling voltage signal; The first input end of the current control loop receives a reference current signal, and the second input end of the current control loop receives a sampling current signal.

2. A control unit according to claim 1, characterized in that The voltage control loop comprises, a first resistor, the first end of which is connected with the reference voltage signal; a first switch, the first end of which is connected with the second end of the first resistor, and the second end of which is grounded; a second resistor, the first end of which is connected with the third end of the first switch, and the second end of which is connected with a bias voltage; a third resistor, the first end of which is connected with the first end of the first switch, and the second end of which is grounded; a fourth resistor, the first end of which is connected with the third end of the first switch; a first comparator, the positive input end of which is connected with the second end of the fourth resistor, and the negative input end and the output end of which are connected; a first capacitor, the first end of which is connected with the positive input end of the first comparator, and the second end of which is grounded; a fifth resistor, the first end of which is connected with the output end of the first comparator; a second comparator, the positive input end of which is connected with the second end of the fifth resistor, and the negative input end of which is connected with the sampling voltage signal; a second capacitor and a seventh resistor, which are connected in series and then connected between the negative input end and the output end of the second comparator; a sixth resistor, the first end of which is grounded, and the second end of which is connected with the negative input end of the second comparator; a first diode, the cathode of which is connected with the output end of the second comparator.

3. The control unit of claim 1, wherein, The current control loop comprises, an eighth resistor, the first end of which is connected with the reference current signal; a second switch, the first end of which is connected with the second end of the eighth resistor, and the second end of which is grounded; a ninth resistor, the first end of which is connected with the third end of the second switch, and the second end of which is connected with a bias voltage; a tenth resistor, the first end of which is connected with the first end of the second switch, and the second end of which is grounded; an eleventh resistor, the first end of which is connected with the third end of the second switch; a third comparator, the positive input end of which is connected with the second end of the eleventh resistor, and the negative input end and the output end of which are connected; a third capacitor, the first end of which is connected with the positive input end of the third comparator, and the second end of which is grounded; a twelfth resistor, the first end of which is connected with the output end of the third comparator; a fourth comparator, the positive input end of which is connected with the second end of the twelfth resistor; a fourth capacitor and a fourteenth resistor, which are connected in series and then connected between the negative input end and the output end of the fourth comparator; a thirteenth resistor, the first end of which is connected with the sampling current signal, and the second end of which is connected with the negative input end of the fourth comparator; a second diode, the cathode of which is connected with the output end of the fourth comparator.

4. A circuit applied to a street lamp, characterized by comprising: The AC / DC conversion module, the input end of which is connected with AC power, and the output end of which is connected in parallel with a DC bus, outputs a bus voltage; the first DC / DC conversion module, the input end of which is connected with the output end of the AC / DC conversion module, and the output end of which is connected in parallel with a battery; ​ A second DC / DC conversion module, an input end of which is connected with an output end of the AC / DC conversion module, and an output end of which is connected with the LED load in parallel; A control unit, comprising a voltage control loop, a current control loop and a driving signal generation module, an output end of the voltage control loop being connected with a cathode of a first diode, an output end of the current control loop being connected with a cathode of a second diode, an anode of the first diode and an anode of the second diode being connected in parallel and then being connected with the driving signal generation module in series; A first input end of the voltage control loop receives a reference voltage signal; a second input end of the voltage control loop receives a sampling voltage signal of the DC bus; A first input end of the current control loop receives a reference current signal; A second input end of the current control loop receives a sampling current signal of the DC bus.

5. The circuit for a street light according to claim 4, wherein: The AC / DC conversion module comprises a third diode, a fourth diode, a fifth diode and a sixth diode, a cathode of the third diode being connected with a cathode of the fourth diode, an anode of the fourth diode being connected with a cathode of the sixth diode, an anode of the sixth diode being connected with an anode of the fifth diode, a cathode of the fifth diode being connected with an anode of the third diode, a first end of the AC power being connected with the anode of the third diode, and a second end of the AC power being connected with the anode of the fourth diode.

6. The circuit applied to the street lamp according to claim 5, characterized in that: The AC / DC conversion module further comprises a fifth capacitor, one end of which is connected with the cathode of the fourth diode, and the other end of which is connected with the anode of the fifth diode, A first transformer, a first end of a primary winding of which is connected with the cathode of the fourth diode, and a second end of a secondary winding of which is connected with a secondary ground end, A third switch tube, a first end of which is connected with a second end of the primary winding of the first transformer, A fifteenth resistor, one end of which is connected with a second end of the third switch tube, and the other end of which is connected with a primary ground end, A fourth switch tube, a second end of which is connected with a first end of the secondary winding of the first transformer, A sixth capacitor, a first end of which is connected with a first end of the fourth switch tube, and a second end of which is connected with a second end of the secondary winding of the first transformer, and two ends of the sixth capacitor being connected with the input end of the first DC-DC conversion module.

7. The circuit for a street light according to claim 6, wherein: The first DC-DC conversion module comprises a seventh capacitor, which is connected with the sixth capacitor in parallel, A fifth switch tube, a first end of which is connected with a first end of the seventh capacitor, A sixth switch tube, a first end of which is connected with a second end of the fifth switch tube, and a second end of which is connected with a second end of the seventh capacitor and a negative electrode of the battery, A first inductor, a first end of which is connected with a first end of the sixth switch tube, and a second end of which is connected with a positive electrode of the battery, An eighth capacitor, a first end of which is connected with a second end of the first inductor, and a second end of which is connected with a second end of the sixth switch tube.

8. The circuit applied to the street lamp according to claim 7, characterized in that: The second DC-DC conversion module comprises a ninth capacitor, a first end of which is connected with a first end of the fourth switch tube, and a second end of which is connected with the secondary ground end, A second inductor, a first end of which is connected with a first end of the ninth capacitor, A seventh switch tube, a first end of which is connected with a second end of the second inductor, and a second end of which is connected with a second end of the ninth capacitor, a seventh diode, an anode of which is connected to the first end of the seventh switch tube, and a cathode of which is connected to the first end of the LED load, a tenth capacitor, a first end of which is connected to the cathode of the seventh diode, and a second end of which is connected to the second end of the seventh switch tube, a sixteenth resistor, one end of which is connected to the second end of the tenth capacitor, and the other end of which is connected to the second end of the LED load.

9. The circuit applied to the street lamp according to claim 4, wherein: when there is AC input but the LED load is not working, the battery is in charging mode, the output current of the DC bus is lower than the constant current setting value, the AC / DC conversion module is controlled to work in constant voltage mode or constant current mode, and the maximum charging power of the battery is limited; when there is AC input and the LED load is working, the battery is not in charging / discharging mode, the output current of the DC bus is lower than the constant current setting value, the AC / DC conversion module is controlled to work in constant voltage mode, and the output current of the LED load is constant; when there is AC input and the LED load is working, the battery is in charging mode, the output current of the DC bus is equal to the constant current setting value, the AC / DC conversion module is controlled to work in constant current or constant voltage mode, the maximum charging power of the battery is limited, and the output current of the LED load is constant; when there is no AC input but the LED load is working, the battery is in discharging mode, the AC / DC conversion module stops working, the battery supplies power to the LED load through the first DC / DC conversion module and the second DC / DC conversion module, and the output current of the LED load is constant.

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