CN109980921B - Switch constant current controller and switch constant current power supply driving circuit - Google Patents
Switch constant current controller and switch constant current power supply driving circuit Download PDFInfo
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- CN109980921B CN109980921B CN201711447520.7A CN201711447520A CN109980921B CN 109980921 B CN109980921 B CN 109980921B CN 201711447520 A CN201711447520 A CN 201711447520A CN 109980921 B CN109980921 B CN 109980921B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/1563—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators without using an external clock
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Abstract
The invention provides a switch constant current controller and a switch constant current power supply driving circuit, comprising: the device comprises an output voltage detection pin, a grounding pin, a grid pin, a drain pin, an electrostatic discharge device and a driving module; the grid pin is connected with a grid of an external power switch tube; the drain electrode pin is connected with the drain electrode of the power switch tube; the electrostatic discharge device comprises an NMOS tube, the source electrode of the NMOS tube is grounded, and the drain electrode of the NMOS tube is connected with the output voltage detection pin; the driving module is connected with a grid electrode of the NMOS tube and a grid electrode pin and is used for controlling the power switch tube and the NMOS tube to be conducted or cut off in the same time so as to ensure that a parasitic reverse body diode of the NMOS tube is not conducted when the voltage at the output voltage detection pin is negative. The invention can effectively reduce the risk of the controller triggering latch-up effect and can reduce the offset of reference voltage and reference current.
Description
Technical Field
The invention relates to the field of switching power supply control, in particular to a switching constant current controller and a switching constant current power supply driving circuit.
Background
The switching constant-current power supply is widely applied to an illumination LED driving power supply, and provides constant driving current for a load LED lamp string so as to keep the brightness of the LED lamp to be continuously stable. The non-isolation Buck conversion (non-isolation Buck) circuit structure is a common structure of a constant current driving power supply of a lighting LED switch. When a power switch tube in the existing non-isolated Buck circuit structure is switched on, a power supply V at a switch endSWApproximately equal to the input voltage VINI.e. the voltage at the Ground (GND) pin of the controller is approximately equal to the input voltage VINThe voltage detection divider resistor is terminated with an OUT + terminal, and because the output voltage in the non-isolated Buck structure is always greater than the input voltage, the output voltage detection pin (DET) pin voltage V of the controllerDETThe voltage of the GND pin, which is lower than the control, i.e., the voltage of the DET pin, is negative. When the controller is in a working state, the negative pressure introduced by the DET pin of the controller easily causes starting leakage of a parasitic bipolar device in the controller, the possibility of failure caused by triggering latch-up effect of the controller due to the starting of the parasitic device is greatly increased, and the deviation of reference voltage and current in the controller caused by the leakage is more likely to occur, so that the constant current performance of the whole system is reduced.
Disclosure of Invention
The invention provides a switch constant current controller, which at least comprises: the device comprises an output voltage detection pin, a grounding pin, a current sampling pin, a grid pin, a drain pin, an electrostatic discharge device and a driving module; wherein,
the grid pin is connected with a grid of an external power switch tube;
the drain electrode pin is connected with the drain electrode of the power switch tube;
the electrostatic discharge device comprises an NMOS tube, the source electrode of the NMOS tube is grounded, and the drain electrode of the NMOS tube is connected with the output voltage detection pin;
the driving module is connected with the grid of the NMOS tube and the grid pin and used for controlling the power switch tube and the NMOS tube to be switched on or switched off within the same time so as to ensure that a parasitic reverse body diode of the NMOS tube is not switched on when the voltage at the output voltage detection pin is negative.
Preferably, the switching constant current controller is one of a non-isolated switching constant current controller, a non-isolated buck conversion switching constant current controller, a non-isolated boost conversion switching constant current controller, an isolated buck conversion switching constant current controller and an isolated boost conversion switching constant current controller.
Preferably, the switching constant current controller is a non-isolated step-down conversion switching constant current controller, and the switching constant current controller further includes:
the sampling filtering module is connected with the current sampling pin and is used for filtering the current signal acquired by the current sampling pin to generate a current mean value signal of the acquired current signal;
the constant current adjusting module is connected with the sampling filtering module and is used for performing constant current processing on the current mean value signal obtained by the sampling filtering module to generate a constant current signal;
the on-time generation module is connected with the constant current adjustment module and used for generating turn-off signals of the power switch tube and the NMOS tube according to the constant current signal;
the inductive current zero-crossing detection module is connected with the drain electrode of the NMOS tube and the output voltage detection pin and is used for generating a switching-on signal of the power switch tube and the NMOS tube when the drain-source voltage of the power switch tube is the lowest;
and the control logic module is connected with the conduction time generation module, the inductive current zero-crossing detection module and the driving module, and is used for controlling the driving module to drive the NMOS tube and the power switch tube to be conducted according to the turn-on signal and controlling the driving module to drive the NMOS tube and the power switch tube to be turned off according to the turn-off signal.
Preferably, the switching constant current controller further includes an overcurrent detection module connected to the current sampling pin and the control logic module, and the overcurrent detection module and the control logic module perform overcurrent protection on the power switching tube together.
Preferably, the switching constant current controller further includes an output overvoltage detection module connected to the output voltage detection pin and the control logic module, and the output overvoltage detection module and the control logic module perform overvoltage protection on the output voltage together.
Preferably, when the power switch tube and the NMOS tube are turned off, the reverse body diode of the NMOS tube clamps the voltage of the output voltage detection pin at-0.7V.
In order to achieve the above and other related objects, the present invention further provides a switching constant current power supply driving circuit, which at least includes:
the switching constant current controller according to any one of the above aspects;
the voltage input module is connected with the drain electrode of the power switch tube;
and the main circuit is connected with the voltage input module and the switch constant current controller.
Preferably, the voltage input module includes an ac power supply, a fuse, and a rectifying and filtering unit, an input end of the rectifying and filtering unit is connected to the ac power supply via the fuse, and an output end of the rectifying and filtering unit is connected to a drain of the power switching tube.
Preferably, the rectifying and filtering unit includes a rectifier and a first capacitor, an input end of the rectifier is connected to the ac power supply via the fuse, a first output end of the rectifier is grounded, a second output end of the rectifier is connected to a drain of the power switching tube, one end of the first capacitor is connected to a second output end of the rectifier, and the other end of the first capacitor is grounded.
Preferably, the main circuit is a non-isolated buck-type conversion circuit, and the main circuit includes: the circuit comprises a power switch tube, an inductor, a sampling resistor, a first resistor, a second capacitor, a freewheeling diode and an output end; wherein,
the freewheeling diode, the sampling resistor, the inductor and the second capacitor are sequentially connected in series; the cathode of the freewheeling diode is connected with the sampling resistor, the anode of the freewheeling diode is grounded, and the connection contact points of the freewheeling diode and the sampling resistor are connected with the current sampling pin; the upper polar plate of the second capacitor is connected with the inductor, and the lower polar plate of the second capacitor is grounded;
the grid electrode of the power switch tube is connected with the grid electrode pin, the drain electrode of the power switch tube is connected with the drain electrode pin, and the source electrode of the power switch tube is connected with the current sampling pin;
the connection contact of the sampling resistor and the inductor is connected with the grounding pin;
the first resistor is connected with the second resistor in series and then connected with the inductor in parallel; the connecting contact points of the first resistor and the second resistor are connected with the output voltage detection pin;
the output end comprises a positive output end and a negative output end, the positive output end of the output end is connected with the upper polar plate of the second capacitor, and the negative output end is grounded.
As described above, the switching constant current controller and the switching constant current power supply driving circuit of the invention have the following beneficial effects:
according to the switching constant-current controller, the electrostatic discharge device and the external power switch tube are connected to the same driving module, so that the electrostatic discharge device and the external power switch tube are simultaneously switched on or off, the possible switching-on time of a reverse body diode parasitic on the electrostatic discharge device is greatly reduced when the voltage of an output voltage detection pin of the controller is negative voltage, even the switching-on of the reverse body diode parasitic on the electrostatic discharge device can be eliminated, the leakage time of a parasitic NPN (negative-positive-negative) tube formed by the reverse body diode and a peripheral active device is reduced, the risk of triggering a latch effect of the controller is effectively reduced, and the offset of reference voltage and reference current can be reduced.
Drawings
Fig. 1 and fig. 2 are schematic structural diagrams of a switching constant current controller according to a first embodiment of the present invention.
Fig. 3 is a schematic diagram illustrating an operation timing sequence of the switching constant current controller according to the first embodiment of the invention.
Fig. 4 is a schematic structural diagram of a switching constant current power supply driving circuit according to a second embodiment of the present invention.
Description of the element reference numerals
1 switch constant current controller
10 NMOS tube
101 reverse diode
11 drive module
12 sampling filter module
13 constant current adjusting module
14 conduction time generation module
15 inductive current zero-crossing detection module
16 control logic module
17 overcurrent detection module
18 output overvoltage detection module
2 main circuit
21 power switch tube
22 inductance
23 sampling resistor
24 first resistance
25 second resistance
26 second capacitance
27 freewheel diode
3 voltage input module
31 AC power supply
32 fuse
33 rectifying and filtering unit
331 rectifier
332 first capacitor
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
Example one
Referring to fig. 1, the present invention provides a switching constant current controller 1, where the switching constant current controller 1 at least includes: the electrostatic discharge device comprises an output voltage detection pin DET, a grounding pin GND, a grid pin Gate, a Drain pin Drain, an electrostatic discharge device 10 and a driving module 11; the Gate pin Gate is connected with a Gate of an external power switch tube 21; the Drain pin Drain is connected with the Drain of the power switch tube 21; the electrostatic discharge device comprises an NMOS tube 10, the source electrode of the NMOS tube 10 is grounded, and the drain electrode of the NMOS tube 10 is connected with the output voltage detection pin DET; the driving module 11 is connected to the Gate of the NMOS transistor 10 and the Gate pin Gate, and is configured to control the power switch transistor 21 and the NMOS transistor 10 to turn on or off within the same time, so as to ensure that the parasitic reverse body diode 101 of the NMOS transistor 10 is not turned on when the voltage at the output voltage detection pin DET is negative.
As an example, the switching constant current controller 1 is a non-isolated switching constant current controller, a non-isolated buck converter constant current controller, a non-isolated boost converter constant current controller, an isolated switch constant current controller, an isolated buck converter constant current controller, and an isolated boost converter constant current controller.
Specifically, when the driving module 11 of the present invention generates a driving signal Gate to drive the Gate of the external power switch tube 21, another driving signal Gate1 is simultaneously generated to drive the Gate of the NMOS transistor 10, the waveform of the driving signal Gate1 is similar to the phase of the waveform of the driving signal Gate, the signal Gate1 is slightly delayed from the driving signal Gate only at the rising edge and the falling edge, and the high level of the driving signal Gate1 is suitable for driving the NMOS transistor 10 to be turned on.
Preferably, referring to fig. 2, in this embodiment, the switching constant current controller 1 is a non-isolated buck conversion switching constant current controller, and the switching constant current controller 1 further includes: a current sampling pin CS; the sampling filtering module 12 is connected to the current sampling pin CS, and is configured to filter the current signal collected by the current sampling pin CS to generate a current average finger signal of the collected current signal; the constant current adjusting module 13 is connected with the sampling filtering module 12, and is configured to perform constant current processing on the current mean value signal obtained by the sampling filtering module 12 to generate a constant current signal; the on-time generating module 14, the on-time generating module 14 is connected to the constant current adjusting module 13, and is configured to generate turn-off signals of the power switch tube 21 and the NMOS tube 10 according to the constant current signal obtained by the constant current adjusting module 13; the inductive current zero-crossing detection module 15 is connected with the drain of the NMOS transistor 10 and the output voltage detection pin DET, and is configured to generate turn-on signals of the power switch transistor 21 and the NMOS transistor 10 when the drain-source voltage of the power switch transistor 10 is the lowest; and the control logic module 16, where the control logic module 16 is connected to the on-time generation module 14, the inductive current zero-crossing detection module 15, and the driving module 11, and is configured to control the driving module 11 to drive the NMOS transistor 10 and the power switch transistor 21 to be turned on according to the on-signal, and control the driving module 11 to drive the NMOS transistor 10 and the power switch transistor 21 to be turned off according to the off-signal.
As an example, the switching constant current controller 1 further includes an overcurrent detection module 17, the overcurrent detection module 17 is connected to the current sampling pin CS and the control logic module 16, and the overcurrent detection module 17 and the control logic module 16 perform overcurrent protection on the power switching tube 21 together.
As an example, the switching constant current controller 1 further includes an output overvoltage detection module 18, the output overvoltage detection module 18 is connected to the output voltage detection pin DET and the control logic module 16, and the output overvoltage detection module and the control logic module 16 perform overvoltage protection on the output voltage together.
For example, when the power switch tube 21 and the NMOS tube 10 are turned off, the reverse body diode 101 of the NMOS tube 10 may clamp the voltage of the output voltage detection pin DET at-0.7V.
It should be noted that the switching constant current controller 1 may include a chip, and the pins and the modules are all located in the chip.
The switch constant current controller 1 of the invention adopts a pin CS to collect a current signal of an external circuit through the current; the sampling filter module 12 filters the currentFiltering the current signal acquired by the sampling pin CS to obtain a current mean value signal of the acquired current signal; the constant current adjusting module 13 performs constant current processing on the current mean value signal obtained by the sampling filtering module 12 by introducing a reference voltage Vref to obtain a constant current signal; the on-time generating module 14 generates off signals of the power switch tube 21 and the NMOS tube 10 according to the constant current signal; the control logic module 16 controls the driving module 11 to drive the NMOS transistor 10 and the power switch transistor 21 to be turned on according to the turn-on signal, and controls the driving module 11 to drive the NMOS transistor 10 and the power switch transistor 21 to be turned off according to the turn-off signal, that is, controls the turn-on time T of the NMOS transistor 10 and the power switch transistor 21onAnd turn-off time Tteb。
The transient voltage and current waveforms of the switching constant current controller 1 of the present invention are shown in fig. 3, wherein V isCS-VOUTFor the actual switch terminal voltage (i.e. the voltage of the current sampling pin CS), ILThe current adopts the inductive current, V, of an external inductor collected by a pin CSDET-VSWThe relative voltage of the pin DET is detected for the output voltage. The inductive current zero-crossing detection module 15 in the switch constant-current control 1, by determining the voltage variation of the output voltage detection pin DET, combines with the control logic module 16, as shown in fig. 3, at T1At the moment, the driving module 11 drives the power switch tube 21 to turn off, and at the same time, the driving module 11 generates a driving signal Gate1 to drive the NMOS tube 10 to turn off. In each off period, the NMOS transistor 10 is in an off state in a time period when the power switch transistor 21 is turned off, the output voltage detection pin DET can be used to normally detect an externally introduced power supply, and the normal function of the switching constant current controller 1 is not affected. At T3At the moment (i.e. when the drain-source voltage of the power switch tube 21 is the lowest), the driving module 11 drives the power switch tube 21 to be turned on, and at the same time, the driving module 11 sends a driving signal Gate1 to drive the NMOS tube 10 to be turned on, so as to bypass the backward diode 101 parasitic to the NMOS tube 10 and avoid the backward diode 101 from being turned onConduction of the backward diode 101.
When the current of the inductor in the external circuit collected by the power switch tube 21 turn-off device and the current sampling pin CS drops to 0, the parasitic capacitance at the switch end of the switch constant current controller resonates with the inductor, and the actual voltage at the switch end (i.e., the voltage at the current sampling pin) V is obtainedCS-VOUTThe voltage appears sinusoidal oscillation, at which time the relative voltage V of the output voltage detection pin DETDET-VSWA sinusoidal oscillation also occurs, and at this time, the NMOS transistor 10 is not turned on, and the relative voltage V of the output voltage detection pin DETDET-VSWThe lowest value of the voltage oscillation amplitude is clamped to about-0.7V by the reverse diode 101 parasitized by the NMOS transistor 10. At T3At this moment, the driving module 11 drives the power switch tube 21 to be turned on, and at the same time, the NMOS tube 10 is also turned on under the driving of the driving module 11, and the voltage drop of the negative current of the output voltage detection pin DET on the on-resistance of the NMOS tube 1 is smaller than the voltage drop of about 0.7V required for the turn-on of the backward diode 101, so that the backward diode 101 is bypassed and is no longer turned on when the power switch tube 21 turns on the device thereafter. Since the reverse diode 101 parasitic to the NMOS transistor 10 is no longer turned on, a parasitic NPN transistor formed by the reverse diode 101 as a emitter junction cannot be turned on, and leakage from the parasitic NP transistor can be eliminated.
The switch constant current controller 1 of the invention can greatly reduce the possible conduction time of the NMOS tube 10 at the output voltage detection pin DET, thereby greatly reducing or completely eliminating the leakage time of a parasitic NPN tube formed by the reverse diode 101 parasitized by the NMOS tube 10 and peripheral active devices on the switch constant current controller 1, further effectively reducing the risk of triggering latch effect of the switch constant current controller 1, and reducing the offset of reference voltage or reference current.
Example two
Referring to fig. 4, the present invention further provides a switching constant current power supply driving circuit, which at least includes: the switching constant current controller 1, the voltage input module 3, and the main circuit 2 according to the first embodiment, wherein the specific structure of the switching constant current controller 1 refers to the first embodiment and will not be described again; the voltage input module 3 is connected with a drain electrode of the power switch tube 21 and is used for providing input voltage for the switch constant current controller 1 and the main circuit 2; the main circuit 2 is connected with the voltage input module 3 and the switch constant current controller 1 and is used for generating constant current drive.
As an example, the voltage input module 31 includes an ac power supply 31, a fuse 32 and a rectifying and filtering unit 33, and the ac power supply 31 and VACLAnd VACNThe two input ends are connected, the input end of the rectifying and filtering unit 33 is connected with the alternating current power supply 31 through the fuse 32, and the output end of the rectifying and filtering unit 33 is connected with the drain electrode of the power switch tube 21. Preferably, in this embodiment, the rectifying and filtering unit 33 includes a rectifier 331 and a first capacitor 332, an input end of the rectifier 331 is connected to the ac power source 31 through the fuse 32, a first output end of the rectifier 331 is grounded, a second output end of the rectifier 331 is connected to the drain of the power switch tube 21, one end of the first capacitor 332 is connected to the second output end of the rectifier 331, and the other end is grounded.
As an example, the main circuit 3 may be one of a non-isolated buck-type conversion circuit, a non-isolated boost-type conversion circuit, an isolated buck-type conversion circuit, and an isolated boost-type conversion circuit.
As an example, in this embodiment, the main circuit 3 is a non-isolated buck-type conversion circuit, and the main circuit 3 includes: the power switch tube 21, the inductor 22, the sampling resistor 23, the first resistor 24, the second resistor 25, the second capacitor 26, the freewheeling diode 27 and the output end; the freewheeling diode 27, the sampling resistor 23, the inductor 22 and the second capacitor 26 are sequentially connected in series; the cathode of the freewheeling diode 27 is connected to the sampling resistor 23, the anode of the freewheeling diode 27 is grounded, and the connection contact points of the freewheeling diode 27 and the sampling resistor 23 are connected to the current sampling pin CS of the switching constant current controller 1; the upper plate of the second capacitor 26 is connected to the inductor 22, and the lower plate of the second capacitor 26 is grounded; the grid electrode of the power switch tube 21 is connected with the grid electrode pin Gate of the switch constant current controller 1, the Drain electrode of the power switch tube 21 is connected with the Drain electrode pin Drain of the switch constant current controller 1, and the source electrode of the power switch tube 21 is connected with the current sampling pin CS of the switch constant current controller 1; the connection contact points of the sampling resistor 23 and the inductor 22 are connected with the ground pin GND of the switching constant current controller 1; the first resistor 24 is connected in series with the second resistor 25 and then connected in parallel with the inductor 22; the connecting contacts of the first resistor 24 and the second resistor 25 are connected with the output voltage detection pin DET of the switching constant current controller 1; the output end comprises a positive output end OUT + and a negative output end OUT-, the positive output end OUT + of the output end is connected with the upper polar plate of the second capacitor 26, and the negative output end OUT-is grounded.
As an example, the power switch tube 21 is a high voltage power switch tube.
In the switching constant-current power supply driving circuit of the present invention, Alternating Current (AC) mains power provided by the AC power supply 31 is rectified by the rectifier 331 (i.e., full-wave rectifier bridge), and filtered by the first capacitor 332 (i.e., input capacitor), and is used as the voltage input of the switching constant-current power supply driving circuit; the switching constant current controller 1 controls the switching action of the power switch tube 21 and the high-voltage chopping voltage (V) according to the sampled inductive current information of the inductor 22CS-VOUT-) After being filtered by the inductor 22 and the second capacitor 26 (i.e., the output capacitor), the output terminal of the switching constant-current power supply driving circuit generates a constant current output and outputs a voltage VOUTLower than the input voltage VIN(ii) a The sampling resistor 23 is used as a sampling resistor of the inductance current of the inductor 22; the output voltage detection pin DET of the switch constant current controller 1 is connected in series with the grounding pin GND through a positive output end OUT + bridged on the switch constant current power supply driving circuitThe voltage dividing resistors (i.e. the first resistor 24 and the second resistor 25) detect the output voltage and provide protection when the output voltage is over-voltage.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (9)
1. A switching constant current controller comprising at least: the device comprises an output voltage detection pin, a grounding pin, a grid pin, a drain pin, an electrostatic discharge device and a driving module; wherein,
the grid pin is connected with a grid of an external power switch tube;
the drain electrode pin is connected with the drain electrode of the power switch tube;
the electrostatic discharge device comprises an NMOS tube, the source electrode of the NMOS tube is grounded, and the drain electrode of the NMOS tube is connected with the output voltage detection pin;
the driving module is connected with a grid electrode of the NMOS tube and a grid electrode pin and is used for controlling the power switch tube and the NMOS tube to be switched on or switched off within the same time so as to ensure that a parasitic reverse body diode of the NMOS tube is not switched on when the voltage at the output voltage detection pin is negative;
the switch constant current controller is a non-isolation step-down type conversion switch constant current controller, and the switch constant current controller further comprises:
a current sampling pin;
the sampling filtering module is connected with the current sampling pin and is used for filtering the current signal acquired by the current sampling pin to generate a current mean value signal of the acquired current signal;
the constant current adjusting module is connected with the sampling filtering module and is used for performing constant current processing on the current mean value signal obtained by the sampling filtering module to generate a constant current signal;
the on-time generation module is connected with the constant current adjustment module and used for generating turn-off signals of the power switch tube and the NMOS tube according to the constant current signal;
the inductive current zero-crossing detection module is connected with the drain electrode of the NMOS tube and the output voltage detection pin and is used for generating a switching-on signal of the power switch tube and the NMOS tube when the drain-source voltage of the power switch tube is the lowest;
and the control logic module is connected with the conduction time generation module, the inductive current zero-crossing detection module and the driving module, and is used for controlling the driving module to drive the NMOS tube and the power switch tube to be conducted according to the turn-on signal and controlling the driving module to drive the NMOS tube and the power switch tube to be turned off according to the turn-off signal.
2. The switching constant current controller according to claim 1, wherein: the switch constant current controller is one of a non-isolation switch constant current controller, a non-isolation step-down type conversion switch constant current controller, a non-isolation step-up type conversion switch constant current controller, an isolation step-down type conversion switch constant current controller and an isolation step-up type conversion switch constant current controller.
3. The switching constant current controller according to claim 1, wherein: the switch constant current controller also comprises an overcurrent detection module which is connected with the current sampling pin and the control logic module, and the overcurrent detection module and the control logic module carry out overcurrent protection on the power switch tube together.
4. A switching constant current controller according to claim 1 or 3, characterized in that: the switch constant current controller also comprises an output overvoltage detection module which is connected with the output voltage detection pin and the control logic module, and the output overvoltage detection module and the control logic module carry out overvoltage protection on the output voltage together.
5. The switching constant current controller according to claim 1, wherein: when the power switch tube and the NMOS tube are turned off, the reverse body diode of the NMOS tube clamps the voltage of the output voltage detection pin at-0.7V.
6. A switching constant current power supply driving circuit, characterized by comprising at least:
the switching constant current controller according to any one of claims 1 to 5;
the voltage input module is connected with the drain electrode of the power switch tube;
and the main circuit is connected with the voltage input module and the switch constant current controller.
7. The switching constant-current power supply driving circuit according to claim 6, wherein: the voltage input module comprises an alternating current power supply, a fuse and a rectification filter unit, wherein the input end of the rectification filter unit is connected with the alternating current power supply through the fuse, and the output end of the rectification filter unit is connected with the drain electrode of the power switch tube.
8. The switching constant-current power supply driving circuit according to claim 7, wherein: the rectifying and filtering unit comprises a rectifier and a first capacitor, the input end of the rectifier is connected with the alternating current power supply through the fuse, the first output end of the rectifier is grounded, the second output end of the rectifier is connected with the drain electrode of the power switch tube, one end of the first capacitor is connected with the second output end of the rectifier, and the other end of the first capacitor is grounded.
9. The switching constant-current power supply driving circuit according to claim 8, wherein: the main circuit is a non-isolated buck conversion circuit, and comprises: the circuit comprises a power switch tube, an inductor, a sampling resistor, a first resistor, a second capacitor, a freewheeling diode and an output end; wherein,
the freewheeling diode, the sampling resistor, the inductor and the second capacitor are sequentially connected in series; the cathode of the freewheeling diode is connected with the sampling resistor, the anode of the freewheeling diode is grounded, and the connection contact points of the freewheeling diode and the sampling resistor are connected with the current sampling pin; the upper polar plate of the second capacitor is connected with the inductor, and the lower polar plate of the second capacitor is grounded;
the grid electrode of the power switch tube is connected with the grid electrode pin, the drain electrode of the power switch tube is connected with the drain electrode pin, and the source electrode of the power switch tube is connected with the current sampling pin;
the connection contact of the sampling resistor and the inductor is connected with the grounding pin;
the first resistor is connected with the second resistor in series and then connected with the inductor in parallel; the connecting contact points of the first resistor and the second resistor are connected with the output voltage detection pin;
the output end comprises a positive output end and a negative output end, the positive output end of the output end is connected with the upper polar plate of the second capacitor, and the negative output end is grounded.
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| CN112953483A (en) * | 2019-11-26 | 2021-06-11 | 湖南中烟工业有限责任公司 | Ultrasonic atomization piece full wave drive circuit, ultrasonic wave electron cigarette |
| CN113890315B (en) * | 2020-07-03 | 2023-08-22 | 圣邦微电子（北京）股份有限公司 | Control circuit and control method of switching converter and switching converter |
| CN112379204B (en) * | 2020-11-18 | 2024-03-29 | 苏州美思迪赛半导体技术有限公司 | Driving port state detection circuit and method of driving circuit |
| CN116565820B (en) * | 2023-07-10 | 2023-10-31 | 荣耀终端有限公司 | Antistatic protection circuit and electronic equipment |
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| CN101420220A (en) * | 2007-10-22 | 2009-04-29 | 华邦电子股份有限公司 | Latch guarding device |
| CN103312309A (en) * | 2013-05-14 | 2013-09-18 | 无锡华润矽科微电子有限公司 | Analog switch control circuit structure |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101420220A (en) * | 2007-10-22 | 2009-04-29 | 华邦电子股份有限公司 | Latch guarding device |
| CN103312309A (en) * | 2013-05-14 | 2013-09-18 | 无锡华润矽科微电子有限公司 | Analog switch control circuit structure |
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