CN209913692U - Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter - Google Patents
Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter Download PDFInfo
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- CN209913692U CN209913692U CN201920902443.8U CN201920902443U CN209913692U CN 209913692 U CN209913692 U CN 209913692U CN 201920902443 U CN201920902443 U CN 201920902443U CN 209913692 U CN209913692 U CN 209913692U
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Abstract
The utility model discloses an on-vehicle DCDC converter primary voltage sampling circuit of low pressure side power supply, including primary voltage sampling circuit, isolating circuit and singlechip sampling circuit, isolating circuit's input links to each other with primary voltage sampling circuit's output, and isolating circuit's output links to each other with singlechip sampling circuit's input. According to the primary voltage sampling circuit of the vehicle-mounted DCDC converter powered by the low-voltage side, the higher the input bus voltage is, the faster the charging time of the capacitor C1 is, the smaller the duty ratio of the generated PWN wave is, the lower the input bus voltage is, the slower the charging time of the capacitor C1 is, the larger the duty ratio of the generated PWN wave is, so that the change of the bus voltage can be monitored in real time according to the change of the duty ratio; the whole is simple and effective, the reliability is high, an isolated power supply is not required to be additionally provided, the board distribution space of the PCB is saved, and the product cost is saved.
Description
Technical Field
The utility model relates to a vehicle mounted power supply equipment technical field specifically is a vehicle-mounted DCDC converter primary voltage sampling circuit of low pressure side power supply.
Background
In power supply products, a primary side direct current voltage and a secondary side direct current voltage are often sampled through a single chip microcomputer AD sampling port and monitored in real time, but in the prior art, a primary side or a secondary side group of isolation power supplies are needed to be provided, so that a winding needs to be added to an auxiliary power transformer to realize isolation, or an isolated DCDC module needs to be added to realize the isolation voltage supply; the traditional bus voltage isolation sampling circuit needs to provide one path of isolation DCDC power supply, so that an isolation power supply chip or an auxiliary power supply transformer winding needs to be added, the board distribution area of a PCB is increased, and the product cost is increased; based on the above problem, a primary side voltage sampling circuit of a low-voltage side powered vehicle-mounted DCDC converter is provided.
Disclosure of Invention
An object of the utility model is to provide a primary voltage sampling circuit of on-vehicle DCDC converter of low pressure side power supply, it is simple effective to have, and the reliability is high, need not additionally to provide the power of isolation, has saved PCB's cloth board space, has saved the advantage of the cost of product, and it is big to have solved among the prior art PCB board wiring area, has increased product cost's problem.
In order to achieve the above object, the utility model provides a following technical scheme: a primary side voltage sampling circuit of a low-voltage side-powered vehicle-mounted DCDC converter comprises a primary side voltage sampling circuit, an isolation circuit and a single chip microcomputer sampling circuit, wherein the input end of the isolation circuit is connected with the output end of the primary side voltage sampling circuit, and the output end of the isolation circuit is connected with the input end of the single chip microcomputer sampling circuit;
the primary side voltage sampling circuit comprises a resistor R1, a capacitor C1, a discharge triode Q1, a zener diode ZD1 and a diode D2, wherein a collector of the discharge triode Q1 is connected with a resistor R1 in series to be connected with a bus voltage end, the resistor R1 is electrically connected with an input end of a capacitor C1, the capacitor C1 is connected with an emitter of the discharge triode Q1 in parallel, an emitter of the discharge triode Q1 is connected with a primary side ground, an anode of the diode D2 is connected with a collector of a discharge diode Q1, and a cathode of the zener diode ZD1 is respectively connected with one ends of the resistor R1, the capacitor C1, the discharge triode Q1 and the diode D2;
the isolation circuit comprises an isolation optocoupler U1 and an isolation optocoupler U2, wherein a pin 1 of the isolation optocoupler U1 is connected with an anode of a voltage stabilizing diode ZD1, a pin 2 of the isolation optocoupler U1 is connected with a primary side ground PGND, a pin 3 of the isolation optocoupler U2 is connected with a base electrode of a discharge triode Q1, a pin 4 of the isolation optocoupler U2 is connected with a cathode of a diode D2, and a pin 2 of the isolation optocoupler U2 is connected with a secondary side ground AGND;
the single-chip microcomputer sampling circuit comprises a chip U3, a triode Q2, a resistor R2 and a resistor R3, a GPIO interface of the chip U3 is connected in series with a series resistor R3 in series to be connected with a pin 1 of an isolation optocoupler U2, a pin 4 of the chip U1 is respectively connected with an input end of the resistor R2, an eCAP pulse capture module of the chip U3 and a collector of the triode Q2, an input end of the resistor R1 is connected with a secondary side power supply of 3.3V, and an emitter of the triode Q2 is connected with a secondary side ground.
Preferably, the resistor R1 may be a single resistor or a plurality of resistors connected in series.
Preferably, the voltage V of said capacitor C1 is plotted in an exponential curve VMAX (1-e)-t/tc) Ascending, i.e. V = VMAX (1-e)-t/tc)。
Preferably, the GPIO interface of the chip U3 transmits a PWM square wave signal having a duty cycle of 0.5%.
Compared with the prior art, the beneficial effects of the utility model are as follows:
according to the primary side voltage sampling circuit of the vehicle-mounted DCDC converter powered by the low-voltage side, an additional power supply is not required to be provided for the primary side bus voltage sampling circuit, the chip U3 sends a PWM wave with fixed frequency through the GPIO module to control the charging and discharging frequency of bus voltage to the capacitor C1, the Zener diode ZD1 controls the highest charging voltage of the capacitor C1, the highest charging voltage exceeds the clamping voltage of the Zener diode ZD1, the Zener diode is conducted in the reverse direction, the isolation optocoupler U1 is further conducted, the triode Q2 is further conducted, and the eCAP module port of the chip U3 is at a low level; when the charged capacitor C1 does not exceed the clamping voltage of the voltage stabilizing diode ZD1, the voltage stabilizing diode ZD1 is cut off reversely, the isolation optocoupler U1 is further cut off, the triode Q2 is further cut off, and at the moment, the eCAP module port of the chip U3 adopts a high level; therefore, a PWM wave with a corresponding duty ratio is generated at an eCAP module port of the chip U3, the chip U3 corresponds to the primary side bus voltage through the duty ratio of the generated PWM wave, the higher the input bus voltage is, the faster the charging time of the capacitor C1 is, the smaller the duty ratio of the generated PWN wave is, the lower the input bus voltage is, the slower the charging time of the capacitor C1 is, the larger the duty ratio of the generated PWN wave is, and therefore the change of the bus voltage can be monitored at any time according to the change of the duty ratio; the whole is simple and effective, the reliability is high, an isolated power supply is not required to be additionally provided, the board distribution space of the PCB is saved, and the product cost is saved.
Drawings
Fig. 1 is an overall circuit diagram of the present invention;
fig. 2 is a circuit block diagram of the present invention;
fig. 3 is a charging curve diagram of the capacitor of the present invention.
In the figure: 1. a primary side voltage sampling circuit; 2. an isolation circuit; 3. singlechip sampling circuit.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1-3, a primary side voltage sampling circuit of a low-voltage side-powered vehicle-mounted DCDC converter comprises a primary side voltage sampling circuit 1, an isolation circuit 2 and a single chip microcomputer sampling circuit 3, wherein an input end of the isolation circuit 2 is connected with an output end of the primary side voltage sampling circuit 1, and an output end of the isolation circuit 2 is connected with an input end of the single chip microcomputer sampling circuit 3;
the primary side voltage sampling circuit 1 comprises a resistor R1, a capacitor C1, a discharge triode Q1, a voltage stabilizing diode ZD1 and a diode D2, wherein a collector of the discharge triode Q1 is connected with a resistor R1 in series to be connected with a bus voltage end, and the resistor R1 can be a single resistor or a plurality of resistors connected in series to adjust the resistance of the series according to the requirement so as to meet the requirement of the value of a circuit access resistor group; the resistor R1 is electrically connected with the input end of the capacitor C1, the capacitor C1 is connected in parallel with the emitter of the discharge triode Q1, the emitter of the discharge triode Q1 is connected with the ground, wherein the voltage V of the capacitor C1 is in an exponential curve VMAX (1-e)-t/tc) Ascending, i.e. V = VMAX (1-e)-t/tc) I.e. V = VMAX (1-e)-t/tc) Wherein VMAX is a primary bus voltage, tc = R1 × C1 is a time constant, and it can be known that a relationship curve of V/VMAX and t/tc (see fig. 2) is obtained, and when V/VMAX and t/tc are both small, the two are substantially in a linear relationship, so that when a capacitor voltage V and the time constant tc are determined, the bus voltage VMAX and the capacitor charging time t can be seen in a linear relationship; the anode of the diode D2 is connected with the collector of the discharge diode Q1, and the cathode of the zener diode ZD1 is respectively connected with one end of a resistor R1, a capacitor C1, a discharge triode Q1 and a diode D2;
the isolation circuit 2 comprises an isolation optocoupler U1 and an isolation optocoupler U2, a pin 1 of the isolation optocoupler U1 is connected with an anode of a voltage stabilizing diode ZD1, a pin 2 of the isolation optocoupler U1 is connected with a primary side ground PGND, a pin 3 of the isolation optocoupler U2 is connected with a base electrode of a discharge triode Q1, a pin 4 of the isolation optocoupler U2 is connected with a cathode of a diode D2, and a pin 2 of the isolation optocoupler U2 is connected with a secondary side ground AGND;
the single-chip microcomputer sampling circuit 3 comprises a chip U3, a triode Q2, a resistor R2 and a resistor R3, a GPIO interface of the chip U3 is connected in series with a resistor R3 in series and connected with a pin 1 of an isolation optocoupler U2, the GPIO interface of the chip U3 sends a PWM square wave signal with the duty ratio of 0.5%, a pin 4 of the chip U1 is connected with an input end of a resistor R2, an eCAP pulse capture module of the chip U3 and a collector of the triode Q2 respectively, an input end of the resistor R1 is connected with a secondary side power supply of 3.3V, and an emitter of the triode Q2 is connected with a secondary side.
The primary side voltage sampling circuit of the vehicle-mounted DCDC converter with power supplied by the low-voltage side has the following working principle: a GPIO port of a chip U3 sends a PWM square wave signal with 100HZ duty ratio of about 0.5%, the PWM square wave signal controls the on-off of an isolation optocoupler U2 through a current limiting resistor R3, further controls a discharging triode Q1 to be switched on and off at the frequency of 100HZ, further discharges a capacitor C1 at the frequency of 100HZ, and the discharging speed of the capacitor C1 through a discharging triode Q1 is far greater than the charging speed of a high-voltage bus through a resistor R1 to the capacitor C1;
the voltage stabilizing diode ZD1 is used for clamping the voltage of a capacitor C1, the clamping voltage of the voltage stabilizing diode ZD1 is far smaller than the bus voltage, the voltage stabilizing diode ZD1 with the clamping voltage of 5V is selected, when the bus voltage charges the capacitor C1 through a resistor R1, the voltage of the capacitor C1 reaches the clamping voltage of the voltage stabilizing diode ZD1, the voltage stabilizing diode ZD1 is conducted reversely, an isolation optocoupler U1 is further switched on, a triode Q2 is further switched on, and the voltage of a point C is at a low level;
after the electricity is discharged by a discharging triode Q1, the bus voltage charges a capacitor C1 through a resistor R1, the voltage of the capacitor C1 does not reach the clamping voltage of a voltage stabilizing diode ZD1, an isolation optocoupler U1 is turned off, a further triode Q2 is turned off, and the voltage of a point C is at a high level;
after the bus voltage charges a capacitor C1 to the clamping voltage of a voltage stabilizing diode ZD1 through a resistor R1, the voltage at two ends of the capacitor C1 is clamped and kept unchanged, the voltage stabilizing diode ZD1 is conducted in the reverse direction, an isolation optocoupler U1 is further turned on, a triode Q2 is further turned on, the voltage at the C point of an eCAP (pulse capture module) sampling point of a chip U3 is at a low level, so that a PWM wave with a corresponding duty ratio is generated at an eCAP module port of the chip U3, a single chip microcomputer U3 corresponds to the bus voltage at the primary side through the duty ratio of the generated PWM wave, and because the bus voltage VMAX and the capacitor charging time t are in a linear relationship, the higher the bus voltage is, the shorter the capacitor C1 charging time is, and the shorter the time when the voltage at the C point is at; conversely, the lower the bus voltage, the longer the capacitor C1 is charged, and the longer the voltage at point C is kept at a high level, i.e., the larger the duty ratio, so that the change in the bus voltage can be monitored at all times in accordance with the change in the duty ratio.
In summary, the following steps: according to the primary side voltage sampling circuit of the vehicle-mounted DCDC converter powered by the low-voltage side, an additional power supply is not required to be provided for the primary side bus voltage sampling circuit, the chip U3 sends a PWM wave with fixed frequency through the GPIO module to control the charging and discharging frequency of bus voltage to the capacitor C1, the Zener diode ZD1 controls the highest charging voltage of the capacitor C1, the highest charging voltage exceeds the clamping voltage of the Zener diode ZD1, the Zener diode is conducted in the reverse direction, the isolation optocoupler U1 is further conducted, the triode Q2 is further conducted, and the eCAP module port of the chip U3 is at a low level; when the charged capacitor C1 does not exceed the clamping voltage of the voltage stabilizing diode ZD1, the voltage stabilizing diode ZD1 is cut off reversely, the isolation optocoupler U1 is further cut off, the triode Q2 is further cut off, and at the moment, the eCAP module port of the chip U3 adopts a high level; therefore, a PWM wave with a corresponding duty ratio is generated at an eCAP module port of the chip U3, the chip U3 corresponds to the primary side bus voltage through the duty ratio of the generated PWM wave, the higher the input bus voltage is, the faster the charging time of the capacitor C1 is, the smaller the duty ratio of the generated PWN wave is, the lower the input bus voltage is, the slower the charging time of the capacitor C1 is, the larger the duty ratio of the generated PWN wave is, and therefore the change of the bus voltage can be monitored at any time according to the change of the duty ratio; the whole is simple and effective, the reliability is high, an isolated power supply is not required to be additionally provided, the board distribution space of the PCB is saved, and the product cost is saved.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. A primary side voltage sampling circuit of a vehicle-mounted DCDC converter powered by a low-voltage side is characterized by comprising a primary side voltage sampling circuit (1), an isolation circuit (2) and a single chip microcomputer sampling circuit (3), wherein the input end of the isolation circuit (2) is connected with the output end of the primary side voltage sampling circuit (1), and the output end of the isolation circuit (2) is connected with the input end of the single chip microcomputer sampling circuit (3);
the primary side voltage sampling circuit (1) comprises a resistor R1, a capacitor C1, a discharge triode Q1, a zener diode ZD1 and a diode D2, wherein a collector of the discharge triode Q1 is connected in series with a resistor R1 to be connected with a bus voltage end, a resistor R1 is electrically connected with an input end of the capacitor C1, a capacitor C1 is connected in parallel with an emitter of the discharge triode Q1, an emitter of the discharge triode Q1 is connected with a primary side ground, an anode of the diode D2 is connected with a collector of a discharge diode Q1, and a cathode of the zener diode ZD1 is respectively connected with one end of a resistor R1, a capacitor C1, a discharge triode Q1 and a diode D2;
the isolation circuit (2) comprises an isolation optocoupler U1 and an isolation optocoupler U2, a pin 1 of the isolation optocoupler U1 is connected with an anode of a voltage stabilizing diode ZD1, a pin 2 of the isolation optocoupler U1 is connected with a primary side ground PGND, a pin 3 of the isolation optocoupler U2 is connected with a base electrode of a discharge triode Q1, a pin 4 of the isolation optocoupler U2 is connected with a cathode of a diode D2, and a pin 2 of the isolation optocoupler U2 is connected with a secondary side ground AGND;
the single-chip microcomputer sampling circuit (3) comprises a chip U3, a triode Q2, a resistor R2 and a resistor R3, a GPIO interface of the chip U3 is connected in series with a series resistor R3 in series to be connected with a pin 1 of an isolation optocoupler U2, a pin 4 of the chip U1 is respectively connected with an input end of the resistor R2, an eCAP pulse capture module of the chip U3 and a collector of the triode Q2, an input end of the resistor R1 is connected with a secondary side power supply of 3.3V, and an emitter of the triode Q2 is connected with a secondary side ground.
2. The primary voltage sampling circuit of the low-voltage side powered vehicle-mounted DCDC converter of claim 1, wherein: the resistor R1 may be a single resistor or a plurality of resistors connected in series.
3. The primary voltage sampling circuit of the low-voltage side powered vehicle-mounted DCDC converter of claim 1, wherein: the voltage V of the capacitor C1 is plotted exponentially with VMAX (1-e)-t/tc) Ascending, i.e. V = VMAX (1-e)-t/tc)。
4. The primary voltage sampling circuit of the low-voltage side powered vehicle-mounted DCDC converter of claim 1, wherein: the GPIO interface of the chip U3 sends a PWM square wave signal with the duty ratio of 0.5%.
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| CN201920902443.8U CN209913692U (en) | 2019-06-17 | 2019-06-17 | Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter |
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| CN201920902443.8U CN209913692U (en) | 2019-06-17 | 2019-06-17 | Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112104192A (en) * | 2019-06-17 | 2020-12-18 | 浙江续航新能源科技有限公司 | Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter |
| WO2022068062A1 (en) * | 2020-09-30 | 2022-04-07 | 深圳市大疆创新科技有限公司 | Drive control apparatus and gimbal |
| CN116577540A (en) * | 2023-07-13 | 2023-08-11 | 深圳市普兰斯通科技有限公司 | Primary side voltage detection circuit, charging device and electric vehicle |
-
2019
- 2019-06-17 CN CN201920902443.8U patent/CN209913692U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112104192A (en) * | 2019-06-17 | 2020-12-18 | 浙江续航新能源科技有限公司 | Low-voltage side power supply primary side voltage sampling circuit of vehicle-mounted DCDC converter |
| WO2022068062A1 (en) * | 2020-09-30 | 2022-04-07 | 深圳市大疆创新科技有限公司 | Drive control apparatus and gimbal |
| CN116577540A (en) * | 2023-07-13 | 2023-08-11 | 深圳市普兰斯通科技有限公司 | Primary side voltage detection circuit, charging device and electric vehicle |
| CN116577540B (en) * | 2023-07-13 | 2023-09-19 | 深圳市普兰斯通科技有限公司 | Primary side voltage detection circuit, charging device and electric vehicle |
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