CN112092727A - Backlight drive circuit and vehicle - Google Patents
Backlight drive circuit and vehicle Download PDFInfo
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- CN112092727A CN112092727A CN202010974324.0A CN202010974324A CN112092727A CN 112092727 A CN112092727 A CN 112092727A CN 202010974324 A CN202010974324 A CN 202010974324A CN 112092727 A CN112092727 A CN 112092727A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q3/00—Arrangement of lighting devices for vehicle interiors; Lighting devices specially adapted for vehicle interiors
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Abstract
The backlight driving circuit comprises a controller, a switch tube, an inductor, a capacitor and a light source, wherein the controller is configured to be connected with a power supply, the switch tube is configured to control the charging and discharging process of the inductor by the controller, the inductor and the capacitor are both configured to discharge electricity to the light source, and the controller, the switch tube, the inductor, the capacitor and the light source are configured to form a voltage reduction type topology structure under the condition that the voltage of the power supply is greater than the required voltage of the light source; in the case that the voltage of the power supply is less than the required voltage of the light source, the controller, the switching tube, the inductor, the capacitor and the light source are configured to form a boost topology. The backlight driving circuit can be configured into different topological structures according to the voltage of the power supply and the voltage of the light source, so that the requirement of driving the light source can be met, the replacement of components such as a controller and the like is avoided, and the cost is saved.
Description
Technical Field
The present application relates to the field of automotive equipment, and more particularly, to a backlight driving circuit and a vehicle.
Background
With the development of vehicle-mounted electronics, the size of a display screen of a vehicle-mounted system is larger and larger, the driving requirement on backlight of the display screen is higher and higher, and the driving current requirement on the backlight of the display screen is related according to the number and arrangement of backlight LEDs so as to meet the requirements of different display sizes and different brightness.
In the related art, a suitable driving chip can be selected according to the driving voltage of the backlight of the display screen and the requirement of the backlight driving power supply, so as to meet the application of the display screen. Then, when the display screen or the backlight driving power supply is replaced, the backlight driving chip is often required to be replaced to meet the changed scheme application, and a new driving chip is required to be debugged again, which is high in cost.
Disclosure of Invention
The embodiment of the application provides a backlight driving circuit and a vehicle.
The backlight driving circuit comprises a controller, a switch tube, an inductor, a capacitor and a light source, wherein the controller is configured to be connected with a power supply, the switch tube is configured to control the charging and discharging process of the inductor by the controller, the inductor and the capacitor are both configured to discharge electricity to the light source, and the controller, the switch tube, the inductor, the capacitor and the light source are configured to form a voltage reduction type topology structure under the condition that the voltage of the power supply is greater than the required voltage of the light source; in the case that the voltage of the power supply is less than the required voltage of the light source, the controller, the switching tube, the inductor, the capacitor and the light source are configured to form a boost topology.
The backlight driving circuit can be configured into different topological structures according to the voltage of the power supply and the voltage of the light source, so that the requirement of driving the light source can be met, the replacement of components such as a controller and the like is avoided, and the cost is saved.
In some embodiments, in a case that the controller, the switch tube, the inductor, the capacitor and the light source are configured as a buck topology, an input terminal of the controller is connected to a positive terminal of the power source, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is connected to a first terminal of the light source, a second terminal of the light source is grounded, a first terminal of the capacitor is connected to a second terminal of the inductor, a second terminal of the capacitor is grounded, and the switch tube is connected between the input terminal and the output terminal of the controller.
In some embodiments, in a case that the controller, the switch tube, the inductor, the capacitor and the light source are configured as a boost topology, an input terminal of the controller is connected to a positive terminal of the power source, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is grounded, a first terminal of the light source is connected to the positive terminal of the power source, a second terminal of the light source is connected to a negative voltage, a first terminal of the capacitor is connected to the first terminal of the light source, a second terminal of the capacitor is connected to the negative voltage, and the switch tube is connected between the input terminal and the output terminal of the controller.
In some embodiments, the controller, the switching tube, the inductor, the capacitor, and the light source can be configured as a buck-boost topology.
In some embodiments, in a case that the controller, the switching tube, the inductor, the capacitor and the light source are configured as a buck-boost topology, an input terminal of the controller is connected to a positive terminal of the power source, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is connected to a first terminal of the light source, a second terminal of the light source is connected to a negative voltage, a first terminal of the capacitor is connected to a first terminal of the light source, a second terminal of the capacitor is connected to a second terminal of the light source, and the switching tube is connected between the input terminal and an output terminal of the controller.
In some embodiments, the switching tube is integrated within the controller.
In some embodiments, the voltage output by the controller is a PWM voltage signal.
In some embodiments, the backlight driving circuit includes a current sensing element connected to the light source, the current sensing element configured to sense a current of the light source.
In some embodiments, the controller controls the switch tube to be turned on when the current of the light source is less than a preset current.
A vehicle according to an embodiment of the present application includes the backlight driving circuit according to any one of the above embodiments.
The backlight driving circuit can be configured into different topological structures according to the voltage of the power supply and the voltage of the light source, so that the requirement of driving the light source can be met, the replacement of components such as a controller and the like is avoided, and the cost is saved.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a step-down backlight driving circuit according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a boost backlight driving circuit according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a voltage-reducing and voltage-boosting backlight driving circuit according to an embodiment of the present disclosure;
FIG. 4 is a schematic structural view of a vehicle according to an embodiment of the present application; .
Description of the main element symbols:
a backlight driving circuit 1000;
Detailed Description
Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative and are only for the purpose of explaining the present application and are not to be construed as limiting the present application.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the application. To simplify the disclosure of the present application, the components and settings of a specific example are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of brevity and clarity and do not in themselves dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.
Referring to fig. 1 and fig. 2, a backlight driving circuit 1000 according to an embodiment of the present disclosure includes a controller 100, a switching tube 200, an inductor L, a first capacitor C1, and a light source 300. The controller 100 is configured to be connected to a power supply 400. The switching tube 200 is configured to control the charging and discharging process of the inductor L by the controller 100. The inductance L and the first capacitance C1 are each configured to discharge to the light source 300.
In case the voltage of the power supply 400 is greater than the required voltage of the light source 300, the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 are configured as a buck topology. In the case that the voltage of the power supply 400 is less than the required voltage of the light source 300, the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 are configured as a boost topology.
The backlight driving circuit 1000 according to the embodiment of the application can be configured into different topological structures according to the voltage of the power supply 400 and the voltage of the light source 300, so that the requirement of driving the light source 300 can be met, the replacement of components such as the controller 100 and the like is avoided, and the cost is saved.
The controller 100 is used for connecting the power supply 400, and is a core element for controlling the whole backlight driving circuit 1000. In the related backlight driving technology, after one controller 100 is selected according to the driving voltage and the backlight driving power of the display panel backlight, in order to change the related parameters of the backlight driving, another controller 100 must be replaced, which results in excessive resources and costs. In the embodiment of the present application, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 may be configured in different topologies for different backlight driving requirements and different power supplies 400 without changing the controller 100. Therefore, the same controller 100 is used in combination with different topology circuits, and the voltage of different power supplies 400 and the use of the driving light source 300 are met.
In the embodiment of the present application, the power supply 400 may be a dc power supply, and is configured to provide a voltage not greater than 55V for the backlight driving circuit 1000, so as to ensure the power supply of the backlight driving circuit 1000. The switch tube 200 may be a MOSFET tube to control the on and off of the backlight driving circuit 1000. The light source 300 may be a backlight module providing light energy to the lcd.
Illustratively, the controller 100 model may be MPQ2483, and the MPQ2483 model controller 100 is a chip with the switching tube 200 integrated therein. In one embodiment, as shown in fig. 1, when the voltage of the power supply 400 is greater than the required voltage of the light source 300, or in other words, when the required voltage of the light source 300 is less than the voltage of the power supply 400 under the condition that the current of the light source 300 is determined. The MPQ2483 type controller 100, the switching tube 200, the inductor L, the first capacitor C1, and the light source 300 may be configured as a buck type topology. When the switch tube 200 inside the controller 100 is turned on, the loop of the power supply 400 is marked as a dotted line, the power supply 400 charges the inductor L through the controller 100, and the current condition of the loop of the power supply 400 at this time can be known through the inductive resistor R. When the loop current reaches the upper limit value, the switch tube 200 inside the controller 100 is turned off, the inductor L discharges, the loop of the power supply 400 is marked as a dot-dash line, and when the loop current reaches the lower limit value, the switch tube 200 inside the controller 100 is turned on again. Thereby implementing a buck topology for power supply 400. The voltage VOUT output by the buck topology is positive with respect to Ground (GND). The positive pole of the light source 300 is connected with VOUT, and the negative pole of the light source 300 is grounded. In the case of determining the output current, the output voltage is VOUT as calculated by volt-second law equation (1):
VOUT＝D*VIN；……(1)
wherein VIN (4.5V < VIN <55V) is the voltage input by the power supply 400 to the controller 100; d (0< D <1) is the duty cycle of the SW pin output Pulse Width Modulation (PWM) waveform of the controller 100. Duty cycle refers to the proportion of the time that power is applied to the total time in a pulse cycle. For example, pulse sequence duty cycle is 0.25 for a pulse width of 1 μ s and a signal period of 4 μ s (1/4).
In another embodiment, as shown in fig. 2, when the voltage of the power supply 400 is less than the required voltage of the light source 300, or in other words, when the required voltage of the light source 300 is greater than the voltage of the power supply 400 under the condition that the current of the light source 300 is determined. The MPQ2483 type controller 100, the switching tube 200, the inductor L, the first capacitor C1, and the light source 300 may be configured as a boost type topology. When the switching tube 200 inside the controller 100 is turned on, the loop of the power supply 400 is marked as a dotted line, the power supply 400 charges the inductor L through the controller 100, discharges the light source 300 through the first capacitor C1, and the current condition of the loop can be known through the sensing resistor R. When the switch tube 200 inside the controller 100 is turned off, the inductor L discharges, the power supply 400, the inductor L and the light source 300 form a power supply loop, at this time, the power supply 400 loop is marked as a dot-dash line, and when the loop current reaches the lower limit value, the switch tube 200 inside the controller 100 is turned on again. Thereby implementing a boost topology for power supply 400. The voltage VOUT output by the boost topology is positive with respect to Ground (GND). The positive pole of the light source 300 is connected with VOUT, and the negative pole of the light source 300 is grounded. In the case of determining the output current, that is, when the switching tube 200 inside the controller 100 is turned on, the output voltage is VOUT as calculated by the volt-second law equation (2):
VOUT＝VIN/(1-D)；……(2)
wherein VIN is the voltage input to the controller 100 by the power supply 400; d (0< D <1) is the duty cycle of the SW pin output Pulse Width Modulation (PWM) waveform of the controller 100. Duty cycle refers to the proportion of the time that power is applied to the total time in a pulse cycle. For example, pulse sequence duty cycle is 0.25 for a pulse width of 1 μ s and a signal period of 4 μ s (1/4).
When the switch tube 200 inside the controller 100 is turned off, the inductor L discharges, and when the power supply 400, the inductor L and the light source 300 form a power supply loop, the output voltage VOUT is calculated according to the following formula (3):
VOUT＝VIN-VSS；……(3)
wherein VIN is the voltage input to the controller 100 by the power supply 400; VSS is a negative voltage and the second terminal of the inductor L is grounded, so that the inductor L provides power to the light source 300. At this time, the output voltage VOUT is less than 55V, the positive electrode of the light source 300 is connected to VIN, and the negative electrode of the light source 300 is connected to VSS, so as to implement a complete boost circuit.
Referring to fig. 1, in some embodiments, in a case where the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 are configured as a buck topology, the input terminal of the controller 100 is connected to the positive electrode of the power source 400. The first terminal of the inductor L is connected to an output pin of the controller 100. The second terminal of the inductor L is connected to the first terminal of the light source 300. The second terminal of the light source 300 is grounded. A first terminal of the first capacitor C1 is connected to a second terminal of the inductor L. The second terminal of the first capacitor C1 is connected to ground. The switching tube 200 is connected between the input and output terminals of the controller 100.
Thus, a complete buck topology circuit is formed, and the voltage of the power supply 400 can be reduced to a voltage value required by the light source 300.
Illustratively, as shown in fig. 1, the controller 100 may be an MPQ2483, MPQ2483 type controller 100 internally integrating a switching tube 200. The controller 100 is used as a core element of the circuit, the VDD pin of the controller 100 is connected to the positive electrode of the power supply 400, the second capacitor C2 is connected between the VDD pin and the positive electrode of the power supply 400, and the second capacitor C2 plays a role in voltage stabilization, so that current impact when the controller 100 is connected or disconnected with the power supply 400 is avoided. The SW pin of the controller 100 is connected to a first end of the inductor L, and the inductor L discharges when the switching tube 200 is turned off, so that the light source 300 can continuously emit light. The second terminal of the inductor L is connected to the first terminal of the first capacitor C1, and the second terminal of the first capacitor C1 is grounded. The first capacitor C1 is also used to discharge when the switch tube 200 is turned off, so that the light source 300 can continuously emit light. The FB pin of the controller 100 is connected between the sensing resistor R and the second end of the light source 300, and the controller 100 can sense the current in the circuit according to the potential difference between the FB pin and the ground, i.e., the potential difference between the two ends of the sensing resistor R, so that the controller 100 can reasonably control the conduction state of the switching tube 200. For example, when the switch 200 is turned on, the inductor L stores energy, and the first capacitor C1 is continuously charged, such that the first terminal of the first capacitor C1 is at a high level and the second terminal of the first capacitor C1 is at a low level. When the controller 100 detects that the loop current reaches the upper limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned off, the inductor L and the first capacitor C1 are discharged, and when the controller 100 detects that the loop current reaches the lower limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned on again. Therefore, the continuous operation of the buck topology circuit is realized.
Referring to fig. 2, in some embodiments, in a case that the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 are configured as a boost topology, an input terminal of the controller 100 is connected to a positive terminal of the power source 400, a first terminal of the inductor L is connected to an output pin of the controller 100, a second terminal of the inductor L is grounded, a first terminal of the light source 300 is connected to the positive terminal of the power source 400, a second terminal of the light source 300 is connected to a negative voltage, a first terminal of the first capacitor C1 is connected to a first terminal of the light source 300, a second terminal of the first capacitor C1 is connected to the negative voltage, and the switching tube 200 is connected between the input terminal and the output terminal of the controller.
Thus, a complete boost topology circuit is formed, and the voltage of the power supply 400 can be boosted to the voltage value required by the light source 300.
Illustratively, as shown in fig. 2, the controller 100 may be an MPQ2483, MPQ2483 type controller 100 internally integrating a switching tube 200. The controller 100 is used as a core element of the circuit, the VDD pin of the controller 100 is connected to the positive electrode of the power supply 400, the second capacitor C2 is connected between the VDD pin and the positive electrode of the power supply 400, and the second capacitor C2 plays a role in voltage stabilization, so that current impact when the controller 100 is connected or disconnected with the power supply 400 is avoided. The light source 300 is also connected between the pin VDD and the positive electrode of the power supply 400, and the inductor L is matched to provide electric energy for the light source 300 when the switch tube 200 is disconnected. The SW pin of the controller 100 is connected to the first terminal of the inductor L, and the second terminal of the inductor L is grounded. A first terminal of the first capacitor C1 is connected to the positive terminal of the power supply 400 and the second terminal of the light source 300. The first capacitor C1 is used for discharging at the moment when the switching tube 200 is turned off, and plays a role in voltage stabilization and protection of the light source 300. The FB pin of the controller 100 is connected between the sensing resistor R and the second end of the light source 300, and the controller 100 can sense the current in the circuit according to the potential difference between the FB pin and the ground, i.e., the potential difference between the two ends of the sensing resistor R, so that the controller 100 can reasonably control the conduction state of the switching tube 200. For example, when the switch 200 is turned on, the power supply 400 stores energy for the inductor L through the controller 100. The first capacitor C1 and the light source 300 form a small loop, and since the first terminal of the first capacitor C1 is at a high level and the second terminal of the first capacitor C1 is at a low level, the first capacitor C1 discharges, so that the voltage of the light source 300 is stable. When the controller 100 detects that the loop current reaches the upper limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned off, the positive electrode of the power supply 400 is connected to the loop to provide energy for the light source 300, the first capacitor C1 is charged, the inductor L discharges, and when the controller 100 detects that the loop current reaches the lower limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned on again. Therefore, the continuous operation of the boost topology circuit is realized.
Referring to fig. 3, in some embodiments, the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 can be configured to form a buck-boost topology.
Thus, the backlight driving circuit 1000 can satisfy the requirements of voltage boosting and voltage reducing at the same time,
illustratively, the controller 100 model may be MPQ2483, and the MPQ2483 model controller 100 is a chip with the switching tube 200 integrated therein. In yet another embodiment, as shown in fig. 3, when the voltage of the power supply 400 may be greater than or less than the required voltage of the light source 300, the MPQ2483 type controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 may be configured as a buck-boost type topology. When the switching tube 200 inside the controller 100 is turned on, the power supply loop is marked as a dotted line, the power supply 400 charges the inductor L through the controller 100, and discharges the light source 300 through the first capacitor C1, and the current condition of the loop can be known through the sensing resistor R. When the switch tube 200 inside the controller 100 is turned off, the inductor L discharges, the inductor L and the light source 300 form a power supply loop, and at this time, the power supply loop is marked as a dot-dash line, and when the loop current reaches the lower limit value, the switch tube 200 inside the controller 100 is turned on again. Thereby implementing a buck-boost topology for power supply 400. In the case of determining the output current, the output voltage is VOUT as calculated by volt-second law equation (4):
VOUT＝(VIN*D)/(1-D)；……(4)
wherein VIN is the voltage input to the controller 100 by the power supply 400; d (0< D <1) is the duty cycle of the output pwm waveform of the SW pin of the controller 100.
When the switch tube 200 inside the controller 100 is turned off, the inductor L discharges, the inductor L and the light source 300 form a loop, and the output voltage VOUT is calculated according to the following formula (5):
VOUT＝GND-VSS；……(5)
wherein VSS is a negative voltage; GND is the potential of the ground terminal, and the potential is zero.
Referring to fig. 3, in some embodiments, in a case where the controller 100, the switching tube 200, the inductor L, the first capacitor C1 and the light source 300 are configured as a buck-boost topology, the input terminal of the controller 100 is connected to the anode of the power supply 400. The first terminal of the inductor L is connected to an output pin of the controller 100.
A second terminal of the first capacitor C1 is connected to a first terminal of the light source 300. The second terminal of the light source 300 is connected to a negative voltage. A first terminal of the first capacitor C1 is connected to a first terminal of the light source 300. A second terminal of the first capacitor C1 is connected to a second terminal of the light source 300. The switching tube 200 is connected between the input and output terminals of the controller 100.
Thus, a complete buck-boost topology is formed, and the power supply 400 can be stepped down or stepped up to a voltage value required by the light source 300.
Illustratively, as shown in fig. 3, the controller 100 may be an MPQ2483, MPQ2483 type controller 100 internally integrating a switching tube 200. The controller 100 is used as a core element of the circuit, the VDD pin of the controller 100 is connected to the positive electrode of the power supply 400, the second capacitor C2 is connected between the VDD pin and the positive electrode of the power supply 400, and the second capacitor C2 plays a role in voltage stabilization, so that current impact when the controller 100 is connected or disconnected with the power supply 400 is avoided. The SW pin of the controller 100 is connected to the first terminal of the inductor L, the second terminal of the inductor L is connected to the first terminal of the light source 300, and the second terminal of the inductor C is connected between the second terminal of the inductor L and the first terminal of the light source 300 and grounded. The inductor L is charged when the switching tube 200 is turned on. The first terminal of the inductor C is connected to the second terminal of the light source 300, and the first capacitor C1 is used for discharging when the switching tube 200 is turned off, so that the light source 300 can continuously emit light. The FB pin of the controller 100 is connected between the sensing resistor R and the second end of the light source 300, and the controller 100 can sense the current in the circuit according to the potential difference between the FB pin and the ground, i.e., the potential difference between the two ends of the sensing resistor R, so that the controller 100 can reasonably control the conduction state of the switching tube 200. For example, when the switch 200 is turned on, the inductor L stores energy, the first terminal of the first capacitor C1 is at a high level, the second terminal of the first capacitor C1 is at a low level, and the first capacitor C1 continuously discharges to power the light source 300. When the controller 100 detects that the loop current reaches the upper limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned off, the inductor L discharges, the inductor C2 is charged and the light source 300 is powered, and when the controller 100 detects that the loop current reaches the lower limit value through the sensing resistor R, the internal switch tube 200 of the controller 100 is turned on again. Therefore, the continuous operation of the voltage reduction and voltage increase type topological circuit is realized.
Referring to fig. 1, 2 and 3, in some embodiments, the switch 200 is integrated in the controller 100. Thus, the circuit structure can be simplified, so that the backlight driving circuit 1000 is integrated.
Specifically, the controller 100 may use an MPQ2483 type controller 100, such controller 100 integrating the switching tube 200 inside. In the embodiment of the present application, the type of the controller 100 is not limited, and the switching tube 200 may be integrated inside the controller 100, or the switching tube 200 may be disposed between the controller 100 and the inductor L to meet the requirement. When the switching tube 200 is disposed outside the controller 100, the switching tube 200 may be an MOS tube or other switching devices, and in the embodiment of the present application, there is no limitation, and the requirements may be met.
Referring to fig. 1, in some embodiments, the voltage output by the controller 100 is a PWM voltage signal. In this way, stability of the operation of the controller 100 and the switching tube 200 is achieved.
Specifically, the PWM voltage signal is a pulse width modulation voltage signal, and the PWM voltage signal is an analog control manner, and the biases of the gates of the controller 100 and the switching tube 200 are modulated according to the change of the corresponding load, so as to change the conduction time of the controller 100 and the switching tube 200, and thus change the output of the regulated power supply 400.
Referring to fig. 1, 2 and 3, in some embodiments, the backlight driving circuit 1000 includes a current detecting element 500. The current sensing element 500 is connected to the light source 300. The current detecting element 500 is configured to detect a current of the light source 300.
In this way, the buck-boost topology of the backlight driver circuit 1000 may be implemented.
In particular, the current sensing element 500 may be a sense resistor R. The FB pin of the controller 100 is connected between the sensing resistor R and the light source 300, and the controller 100 can compare the difference between the potentials at the two ends of the sensing resistor R and the resistance of the sensing resistor R to calculate the current in the loop according to the ohm's law. The controller 100 controls the on/off of the switching tube 200 according to the current value and the preset current value. For example, when the current reaches the upper limit value, the controller 100 controls the switching tube 200 to be turned off; when the current reaches the lower limit value, the controller 100 controls the switching tube 200 to be conducted. In some embodiments, the current sensing element 500 may also be other kinds of circuit elements.
Referring to fig. 1, in some embodiments, when the current of the light source 300 is less than a predetermined current, the controller 100 controls the switch tube 200 to be turned on.
Thus, a stable current is provided, and the continuous operation of the light source 300 is ensured.
Illustratively, as shown in fig. 1, when the loop current is normal, the controller 100 controls the switching tube 200 to conduct. When the loop current reaches the upper limit value, the controller 100 controls the switch tube 200 to be switched off, and when the loop current reaches the lower limit value, the switch tube 200 inside the controller 100 is switched on again. Therefore, the circuit automatically controls the current, the preset interval of the current value floats, and the stability of the backlight driving circuit 1000 is improved.
Referring to fig. 4, a vehicle 2000 according to an embodiment of the present disclosure includes a backlight driving circuit 1000 according to any of the embodiments.
The backlight driving circuit 1000 according to the embodiment of the application can be configured into different topological structures according to the voltage of the power supply 400 and the voltage of the light source 300, so that the requirement of driving the light source 300 can be met, the replacement of components such as the controller 100 and the like is avoided, and the cost is saved.
The vehicle 2000 according to the embodiment of the present invention is not limited to a type, and may be a pure electric vehicle or a hybrid vehicle, and the vehicle 2000 may be provided with the backlight driving circuit 1000 according to any of the above embodiments.
In the description of the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the description herein, references to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present application have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present application, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (10)
1. A backlight driving circuit is characterized by comprising a controller, a switch tube, an inductor, a capacitor and a light source, wherein the controller is configured to be connected with a power supply, the switch tube is configured to control the charging and discharging process of the inductor by the controller, the inductor and the capacitor are both configured to discharge electricity to the light source, and the controller, the switch tube, the inductor, the capacitor and the light source are configured to form a voltage reduction type topology under the condition that the voltage of the power supply is greater than the required voltage of the light source; in the case that the voltage of the power supply is less than the required voltage of the light source, the controller, the switching tube, the inductor, the capacitor and the light source are configured to form a boost topology.
2. The backlight driving circuit of claim 1, wherein in a case where the controller, the switching tube, the inductor, the capacitor and the light source are configured as a buck topology, an input terminal of the controller is connected to a positive terminal of the power source, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is connected to a first terminal of the light source, a second terminal of the light source is grounded, a first terminal of the capacitor is connected to a second terminal of the inductor, a second terminal of the capacitor is grounded, and the switching tube is connected between the input terminal and an output terminal of the controller.
3. The backlight driving circuit of claim 1, wherein in a case where the controller, the switch tube, the inductor, the capacitor and the light source are configured as a boost topology, an input terminal of the controller is connected to a positive terminal of the power source, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is grounded, a first terminal of the light source is connected to the positive terminal of the power source, a second terminal of the light source is connected to a negative voltage, a first terminal of the capacitor is connected to a first terminal of the light source, a second terminal of the capacitor is connected to the negative voltage, and the switch tube is connected between the input terminal and an output terminal of the controller.
4. The backlight driving circuit of claim 1, wherein the controller, the switching tube, the inductor, the capacitor and the light source are configured as a buck-boost topology.
5. The backlight driving circuit of claim 4, wherein in a case that the controller, the switch tube, the inductor, the capacitor and the light source are configured as a buck-boost topology, an input terminal of the controller is connected to a positive terminal of the power supply, a first terminal of the inductor is connected to an output pin of the controller, a second terminal of the inductor is connected to a first terminal of the light source, a second terminal of the light source is connected to a negative voltage, a first terminal of the capacitor is connected to a first terminal of the light source, a second terminal of the capacitor is connected to a second terminal of the light source, and the switch tube is connected between the input terminal and the output terminal of the controller.
6. The backlight driving circuit according to any of claims 1-5, wherein the switching tube is integrated in the controller.
7. The backlight driving circuit according to any of claims 1-5, wherein the voltage output by the controller is a PWM voltage signal.
8. The backlight driving circuit according to any of claims 1-5, wherein the backlight driving circuit comprises a current sensing element connected to the light source, the current sensing element being configured to sense a current of the light source.
9. The backlight driving circuit according to any of claims 1-5, wherein the controller controls the switch tube to be turned on when the current of the light source is less than a predetermined current.
10. A vehicle characterized by comprising the backlight driving circuit according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010974324.0A CN112092727B (en) | 2020-09-16 | 2020-09-16 | Backlight drive circuit and vehicle |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010974324.0A CN112092727B (en) | 2020-09-16 | 2020-09-16 | Backlight drive circuit and vehicle |
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| CN112092727A true CN112092727A (en) | 2020-12-18 |
| CN112092727B CN112092727B (en) | 2022-03-18 |
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| CN112092727B (en) | 2022-03-18 |
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