CN209844567U - Linear charging system and constant-current and constant-voltage control circuit - Google Patents
Linear charging system and constant-current and constant-voltage control circuit Download PDFInfo
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- CN209844567U CN209844567U CN201920206281.4U CN201920206281U CN209844567U CN 209844567 U CN209844567 U CN 209844567U CN 201920206281 U CN201920206281 U CN 201920206281U CN 209844567 U CN209844567 U CN 209844567U
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Abstract
The utility model provides a linear charging system and a constant current and constant voltage control circuit, which comprises a constant current and constant voltage control circuit, a power supply input circuit for supplying power and a battery module for storing energy; wherein, constant current constant voltage control circuit includes: the grid electrode control module is used for adjusting the grid electrode voltage of the current sampling tube and the output power tube based on a voltage sampling feedback signal and a current sampling feedback signal. The utility model discloses a linear charging system and constant current constant voltage control circuit pass through linear control and establish ties N type adjusting tube impedance on current sampling branch road, and no starting current overshoots, solve linear charging management and have the current when starting and overshoot even by its problem that leads to constantly restarting, and can simplify some circuits; and the output current still keeps the current amplification factor with high precision when the output voltage is lower.
Description
Technical Field
The utility model relates to an integrated circuit design and application especially relate to a linear charging system and constant current constant voltage control circuit.
Background
For many years, various linear charge management ICs (integrated circuits) have been developed and widely used to realize control of constant current and constant voltage output in battery charging, and are used in battery management of various portable devices.
In the prior art, the drain voltage of the current sampling tube is consistent with that of the output power tube by controlling the impedance and the voltage drop of the P tube, but the P tube is conducted when the grid voltage of the P tube is at a low level, so that the risk of current overshoot during starting exists. Therefore, in the prior art, overshoot protection is added, for example, when the voltage at the current setting end is greater than 1.2V, the constant-current constant-voltage control module is turned off, but in a severe case, the sample current branch triggers the chip to turn off or restart the chip continuously, so that the chip cannot work normally, as shown in fig. 3, when the input power VIN comes, the chip starts to work, when the overshoot protection is effective (the overshoot protection is performed when the overshoot protection signal SHDN is at a high level), the constant-current constant-voltage control module is turned off, and the output current of the constant-current constant-voltage control module is reduced; when the overshoot protection is invalid (the overshoot protection is not performed when the overshoot protection signal SHDN is at a low level), the constant-current and constant-voltage control module is started, and the output current of the constant-current and constant-voltage control module rises; and the chip cannot work after repeated restarting. In addition, due to the clamping of the source grid of the P tube, the drain voltage of the current sampling tube cannot follow the drain voltage of the output power tube, so that the current amplification factor of the output power tube and the current sampling tube deviates from the set factor.
In summary, finding a method or a technique to avoid the risk that the sampling current branch triggers the chip to turn off or the chip is continuously restarted and to make the output current still maintain the current amplification factor to be more accurate when the output voltage is lower has become one of the problems to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
In view of the above prior art's shortcoming, the utility model aims to provide a linear charging system and constant current constant voltage control circuit for solve among the prior art constant current constant voltage control chip frequently restart, the low grade problem of precision is followed to voltage.
In order to achieve the above objects and other related objects, the present invention provides a constant current and constant voltage control circuit, which comprises at least:
the device comprises a current sampling tube, an output power tube, a voltage following control module, an output voltage sampling module and a grid control module;
the source electrode of the current sampling tube is connected with an input power supply, the grid electrode of the current sampling tube is connected with the output end of the grid electrode control module, the drain electrode of the current sampling tube is connected with the first end of the sampling resistor after passing through the voltage following control module, the second end of the sampling resistor is grounded, and the current sampling tube is used for generating sampling current;
the source electrode of the output power tube is connected with the input power supply, the grid electrode of the output power tube is connected with the output end of the grid electrode control module, and the drain electrode of the output power tube is connected with the output voltage sampling module and used for adjusting output current;
the voltage following control module is connected to the drain electrodes of the current sampling tube and the output power tube and is used for controlling the drain electrode voltage of the current sampling tube to follow the drain electrode voltage of the output power tube, wherein the voltage following control module comprises an operational amplifier and an N-type adjusting tube; the input end of the operational amplifier is respectively connected with the current sampling tube and the drain electrode of the output power tube; the drain electrode of the N-type adjusting tube is connected with the drain electrode of the current sampling tube, the source electrode of the N-type adjusting tube is connected with the first end of the sampling resistor, and the grid electrode of the N-type adjusting tube is connected with the output end of the operational amplifier;
the grid control module is connected with the output voltage sampling module and the first end of the sampling resistor, compares a voltage sampling feedback signal output by the output voltage sampling module with a first calibration voltage, compares a current sampling feedback signal on the sampling resistor with a second calibration voltage, and adjusts the grid voltage of the current sampling tube and the output power tube based on two comparison results, thereby controlling the output voltage value.
Optionally, the constant-current constant-voltage control circuit further includes a constant-current calibration point selection module, where the constant-current calibration point selection module is connected to the drain of the output power tube, compares the drain voltage of the output power tube with a first reference, and outputs a constant-current calibration point selection signal to determine the value of the first calibration voltage.
More optionally, the constant current and constant voltage control circuit further includes a full charge determination module, where the full charge determination module is connected to the first end of the sampling resistor, compares the current sampling feedback signal with a second reference, and outputs a corresponding full charge determination signal.
More optionally, the full charge determination module includes a comparison unit and a nand logic unit; the input end of the comparison unit is respectively connected with the current sampling feedback signal and the second reference; the input end of the NAND logic unit is respectively connected with the comparison unit and the output end of the constant current calibration point selection module, and the full charge judgment signal takes effect when the drain voltage of the output power tube is greater than the first reference and the current sampling feedback signal is less than the second reference.
More optionally, the constant-current constant-voltage control circuit further includes a full-charge shutdown module, the full-charge shutdown module is connected in series in a power-to-ground path of the output power tube, and a control end of the full-charge shutdown module is connected to the full-charge judgment signal.
Optionally, the constant current and constant voltage control circuit further comprises a substrate selection module, wherein the substrate selection module comprises a first diode and a second diode; the anode of the first diode is connected with the input power supply, and the cathode of the first diode is connected with the current sampling tube and the substrate of the output power tube; and the cathode of the second diode is connected with the cathode of the first diode, and the anode of the second diode is connected with the drain electrode of the output power tube.
Optionally, the constant current and constant voltage control circuit further includes a reference voltage generation module, where the reference voltage generation module receives the input power supply and generates a reference voltage and a calibration voltage in the constant current and constant voltage control circuit based on the input power supply.
Optionally, the constant-current and constant-voltage control circuit further includes a pull-up current source, one end of the pull-up current source is connected to the input power supply, and the other end of the pull-up current source is connected to the first end of the sampling resistor.
Optionally, the constant-current constant-voltage control circuit further includes a pull-down current source, one end of the pull-down current source is connected to the output end of the gate control module, and the other end of the pull-down current source is grounded.
To achieve the above and other related objects, the present invention provides a linear charging system, which includes at least:
the constant-current and constant-voltage control circuit, the power supply input circuit and the battery module;
the power supply input circuit is connected with the constant-current constant-voltage control circuit and provides an input power supply for the constant-current constant-voltage control circuit;
the battery module is connected to the drain electrode of the output power tube and used for receiving and storing the electric energy output by the constant-current constant-voltage control circuit.
Optionally, the linear charging system further includes a charging indication circuit, a control end of the charging indication circuit is connected to the full charge judgment signal, and the charging indication circuit is turned off when the linear charging system stops charging.
As described above, the utility model discloses a linear charging system and constant current constant voltage control circuit has following beneficial effect:
the utility model discloses a linear charging system and constant current constant voltage control circuit pass through linear control and establish ties N type adjusting tube impedance on current sampling branch road, and no starting current overshoots, solve linear charging management and have the current when starting and overshoot even by its problem that leads to constantly restarting, and can simplify some circuits; and the output current still keeps the current amplification factor with high precision when the output voltage is lower.
Drawings
Fig. 1 is a schematic diagram illustrating a principle of frequent restart of a constant current and constant voltage control chip in the prior art.
Fig. 2 shows a schematic structural diagram of the constant current and constant voltage control circuit of the present invention.
Fig. 3 is a schematic diagram of the constant current and constant voltage control circuit according to the present invention.
Fig. 4 is a schematic structural diagram of the linear charging system of the present invention.
Description of the element reference numerals
01 Linear charging system
1 constant current and constant voltage control circuit
11 voltage following control module
111 operational amplifier
12 output voltage sampling module
13 constant current calibration point selection module
14 grid control module
15 full charge judging module
151 comparison unit
152 nand logic cell
16 substrate selection module
17 reference voltage generating module
2 power supply input circuit
3 Battery module
31 battery load
4 charging indicating circuit
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
Please refer to fig. 2-4. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the invention in a schematic manner, and only the components related to the invention are shown in the drawings rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, quantity and proportion of the components in actual implementation may be changed at will, and the layout of the components may be more complicated.
Example one
As shown in fig. 2, the present embodiment provides a constant current and constant voltage control circuit 1, where the constant current and constant voltage control circuit 1 includes:
the circuit comprises a current sampling tube M1, an output power tube M2, a voltage following control module 11, an output voltage sampling module 12, a constant current calibration point selection module 13 and a grid control module 14.
As shown in fig. 2, the source of the current sampling tube M1 is connected to an input power VIN, the gate is connected to the output end of the gate control module 14, the drain is connected to the first end of a sampling resistor Rs through the voltage following control module 11, the second end of the sampling resistor Rs is grounded GND, and the current sampling tube M1 is configured to generate a sampling current.
Specifically, in the present embodiment, the current sampling tube M1 is a P-type transistor, including but not limited to an insulated gate bipolar transistor and a metal-oxide semiconductor field effect transistor, which are not described herein again.
As shown in fig. 2, the source of the output power transistor M2 is connected to the input power VIN, the gate thereof is connected to the output end of the gate control module 14, and the drain thereof is connected to the output voltage sampling module 12 for adjusting the output current.
Specifically, in the present embodiment, the output power transistor M2 is a P-type transistor, including but not limited to an insulated gate bipolar transistor and a metal-oxide semiconductor field effect transistor, which is not described herein again. The output power tube M2 and the current sampling tube M1 are of the same device type, and the width-to-length ratio is set as required, in this embodiment, the ratio of the width-to-length ratio of the output power tube M2 to the current sampling tube M1 is 1000: 1.
As shown in fig. 2, the voltage following control module 11 is connected to the current sampling tube M1 and the drain of the output power tube M2, and is configured to control the drain voltage VTR of the current sampling tube M1 to follow the drain voltage BAT of the output power tube M2.
Specifically, in the present embodiment, the voltage follower control module 11 includes an operational amplifier 111 and an N-type tuning transistor N1. The input end of the operational amplifier 111 is connected to the drains of the current sampling tube M1 and the output power tube M2, in this embodiment, the non-inverting input end of the operational amplifier 111 is connected to the drain of the current sampling tube M1, and the inverting input end of the operational amplifier 111 is connected to the drain of the output power tube M2. The drain electrode of the N-type adjusting tube N1 is connected to the drain electrode of the current sampling tube M1, the source electrode is connected to the first end of the sampling resistor Rs, the gate electrode is connected to the output end of the operational amplifier 111, the impedance of the N-type adjusting tube N1 is reduced when the output voltage VMA of the operational amplifier 111 is at a high level, the impedance of the N-type adjusting tube N1 is increased when the output voltage VMA of the operational amplifier 111 is at a low level, and the impedance of the N-type adjusting tube N1 is linearly controlled by the output voltage VMA of the operational amplifier 111, so that the drain voltage of the current sampling tube M1 follows the drain voltage of the output power tube M2.
As an implementation manner of this embodiment, the constant-current and constant-voltage control circuit 1 further includes a pull-up current source S1, where one end of the pull-up current source S1 is connected to the input power VIN, and the other end is connected to the first end of the sampling resistor Rs.
As shown in fig. 2, the output voltage sampling module 12 is connected to the drain of the output power transistor M2, and is configured to reduce the voltage scale of the output terminal BAT of the constant current and constant voltage control circuit 1.
Specifically, in this embodiment, the output voltage sampling module 12 includes a first resistor R1 and a second resistor R2, and the first resistor R1 is connected in series with the second resistor R2 to implement voltage sampling by voltage division, so as to obtain a voltage sampling feedback signal FB. The output voltage sampling module 12 may adopt a circuit capable of implementing sampling with any structure and any device, which is not described herein again.
As shown in fig. 2, the constant current calibration point selection module 13 is connected to the drain of the output power transistor M2, compares the drain voltage of the output power transistor M2 with a first reference, and outputs a constant current calibration point selection signal TRICK.
Specifically, in this embodiment, the constant current calibration point selection module 13 includes a comparator, a positive phase input end of the comparator is connected to the drain of the output power transistor M2 (i.e., the output terminal BAT of the constant current and constant voltage control circuit 1), a negative phase input end of the comparator is connected to the first reference, and the constant current calibration point selection module 13 outputs the constant current calibration point selection signal TRICK. In practical use, the inverter can be added to replace the relationship between the input signal and the input port, and only the logical relationship is required to be satisfied, which is not limited to this embodiment. The first reference may be specifically set according to device parameters of an actual circuit, and is not limited to this embodiment, in which the first reference is 2.9V.
As shown in fig. 2, the gate control module 14 is connected to the output voltage sampling module 12 and the first end of the sampling resistor Rs, compares the voltage sampling feedback signal FB with a first calibration voltage, compares the current sampling feedback signal PROG on the sampling resistor Rs with a second calibration voltage, and adjusts the gate voltages of the current sampling tube M1 and the output power tube M2 based on two comparison results, thereby controlling the voltage value of the output terminal BAT of the constant current and constant voltage control circuit 1.
Specifically, in this embodiment, the first calibration voltage is set to 1.2V, and in actual use, the value of the first calibration voltage may be set according to the resistance values of the first resistor R1, the second resistor R2, and the value range of the output voltage BAT, which is not limited in this embodiment. In this embodiment, the value of the second calibration voltage is selected and determined by the constant current calibration point selection module 13, the value of the second calibration voltage corresponding to the voltage of the output terminal BAT of the constant current and constant voltage control circuit 1 when the voltage of the output terminal BAT of the constant current and constant voltage control circuit 1 is greater than the first reference, and specific values can be set according to device parameters and usage requirementsThe value of the second calibration voltage corresponding to a voltage smaller than the first reference is 0.2V; i.e. when VBATWhen the voltage is more than or equal to 2.9V, the second calibration voltage is 1V, and when V is larger than or equal to 2.9VBATIf the second calibration voltage is less than 2.9V, the second calibration voltage is 0.2V, which is not limited to this embodiment.
It should be noted that, in practical use, the second calibration voltage may be a fixed value, and the constant current calibration point selection module 13 is not required. In this embodiment, the constant current calibration point selection module 13 is added to select the gear of the output current according to the voltage level of the output terminal BAT.
As an implementation manner of this embodiment, the constant-current and constant-voltage control circuit 1 further includes a pull-down current source S2, one end of the pull-down current source S2 is connected to the output end of the gate control module 14, and the other end is grounded.
As an implementation manner of this embodiment, the constant-current constant-voltage control circuit 1 further includes a full charge determination module 15, where the full charge determination module 15 is connected to a first end of the sampling resistor Rs, compares the current sampling feedback signal PROG with a second reference, and outputs a corresponding full charge determination signal STANDBY.
Specifically, in the present embodiment, the full charge determination module 15 includes a comparison unit 151 and a nand logic unit 152. The input terminal of the comparing unit 151 is connected to the current sampling feedback signal PROG and the second reference, respectively, in this embodiment, the non-inverting input terminal of the comparing unit 151 is connected to the second reference, and the non-inverting input terminal of the comparing unit 151 is connected to the current sampling feedback signal PROG. In practical use, the inverter can be added to replace the relationship between the input signal and the input port, and only the logical relationship is required to be satisfied, which is not limited to this embodiment. The input end of the nand logic unit 152 is connected to the comparing unit 151 and the output end of the constant current calibration point selecting module 13, and the full charge determination signal STANDBY is asserted when the drain voltage of the output power transistor M2 is greater than the first reference and the current sampling feedback signal PROG is less than the second reference.
As an implementation manner of this embodiment, the constant-current constant-voltage control circuit 1 further includes a full-charge shutdown module, the full-charge shutdown module is connected in series in a power-to-ground path of the output power transistor M2, and a control end of the full-charge shutdown module is connected to the full-charge judgment signal STANDBY.
Specifically, in this embodiment, the full-charge shutdown module is implemented by using an N-type switching tube N2, the N-type switching tube N2 is connected between the output voltage sampling module 12 and the ground GND, a drain of the N-type switching tube N2 is connected to the output voltage sampling module 12, a source of the N-type switching tube N2 is grounded, and a gate of the N-type switching tube N2 is connected to the full-charge determination signal STANDBY. In practical use, the full charge shutdown module may have any circuit structure for disconnecting the power supply to ground path of the output power transistor M2 when the full charge determination signal STANDBY indicates full charge, and is not limited to the installation position and the device type of this embodiment.
As an implementation manner of this embodiment, the constant current and constant voltage control circuit 1 further includes a substrate selection module 16, and the substrate selection module 16 includes a first diode D1 and a second diode D2. The anode of the first diode D1 is connected with the input power VIN, and the cathode of the first diode D1 is connected with the substrates of the current sampling tube M1 and the output power tube M2; the cathode of the second diode D2 is connected to the cathode of the first diode D1, and the anode of the second diode D2 is connected to the drain of the output power tube M2.
As an implementation manner of this embodiment, the constant-current and constant-voltage control circuit 1 further includes a reference voltage generating module 17, where the reference voltage generating module 17 receives the input power VIN, and generates each reference voltage and calibration voltage in the constant-current and constant-voltage control circuit 1 based on the input power VIN, including but not limited to the first reference (2.9V), the second reference (0.1V), the first calibration voltage (1.2V), the second calibration voltage (1V or 0.2V), and a signal VOK indicating that a voltage after power-on meets an operation requirement.
The working principle of the constant-current constant-voltage control circuit 1 is as follows:
1) based on the voltage following, the drain voltage of the current sampling tube M1 follows the drain voltage of the output power tube M2, and the voltage following control method comprises the following steps:
specifically, the drain voltages of the current sampling tube M1 and the output power tube M2 are compared, and the impedance of the N-type adjusting tube N1 connected in series with the current sampling tube M1 is linearly adjusted based on the drain voltage difference between the current sampling tube M1 and the output power tube M2, so that the drain voltage of the current sampling tube M1 follows the drain voltage of the output power tube M2.
More specifically, when the drain voltage of the output power transistor M2 is higher than the drain voltage of the current sampling transistor M1, the operational amplifier 111 outputs a low level, the impedance of the N-type adjusting transistor N1 increases, and the drain voltage of the current sampling transistor M1 increases; conversely, when the drain voltage of the output power tube M2 is lower than the drain voltage of the current sampling tube M1, the operational amplifier 111 outputs a high level, the impedance of the N-type adjusting tube N1 decreases, and the drain voltage of the current sampling tube M1 decreases; the drain voltages of the current sampling tube M1 and the output power tube M2 are equal through the impedance linear adjustment of the N-type adjusting tube N1.
It should be noted that, the impedance of the N-type adjusting tube N1 is linearly controlled to make the drain voltage of the current sampling tube M1 follow the drain voltage of the output power tube M2, and since the N-type transistor is characterized in that the transistor is not turned on when the gate-source voltage difference is low and is turned on when the gate-source voltage difference is linearly increased, the current flowing through the current sampling tube M1 does not overshoot. As shown in fig. 3, when the input power VIN comes, VOK is activated, the output voltage VMA of the operational amplifier 111 and the current sampling feedback signal PROG both generate corresponding levels, and the output current I of the constant current and constant voltage control circuit 1BATStable output and no overshoot phenomenon, so that the overshoot protection in the prior art is not needed, the circuit structure is simple, and the risk of frequent restarting is avoided.
It should be noted that, when the N-type tuning tube N1 is completely turned on, the current flowsThe voltage value of the drain voltage VTR of the sampling tube M1 may be very close to the voltage value V of the current sampling feedback signalPROGTherefore, when the output voltage of the constant current and constant voltage control circuit 1 is low, the current amplification factors of the output power tube M2 and the current sampling tube M1 are still kept to be not deviated.
2) And adjusting the grid voltages of the current sampling tube M1 and the output power tube M2 based on the voltage sampling feedback signal FB and the current sampling feedback signal PROG, and controlling the output current to be constant and the output voltage to be constant.
Specifically, when the voltage value of the voltage sampling feedback signal FB is higher than the first calibration voltage (1.2V in this embodiment), the gate voltages of the current sampling tube M1 and the output power tube M2 are adjusted to be decreased; when the voltage value of the voltage sampling feedback signal FB is lower than the first calibration voltage, the grid voltage of the current sampling tube M1 and the grid voltage of the output power tube M2 are adjusted to be increased. When the voltage of the current sampling feedback signal PROG is higher than the second calibration voltage (in this embodiment, the second calibration voltage is selected to be 1V or 0.2V by the constant current calibration point selection module 13), the gate voltages of the current sampling tube M1 and the output power tube M2 are adjusted to be decreased; when the voltage of the current sampling feedback signal PROG is lower than the second calibration voltage, the gate voltages of the current sampling tube M1 and the output power tube M2 are adjusted to be increased.
It should be noted that, by the voltage following control method, the voltages of the three poles of the current sampling tube M1 and the output power tube M2 are consistent, so that the currents of the current sampling tube M1 and the output power tube M2 are set multiple times, that is:
wherein, IBATIs the output current, I, of the constant current and constant voltage control circuit 1M2For the current flowing through the output power tube M2, K is a real number greater than 1, IM1For the current flowing through the current sampling tube M1, VPROGIs that it isVoltage value, R, of current sampling feedback signalSIs the resistance value of the sampling resistor. In this example, K is 1000, and V is after constant voltage outputPROGIs 1V or 0.2V. Because the voltages of the three poles of the current sampling tube M1 and the output power tube M2 are consistent, the output after constant current and constant voltage control meets the following relational expression:
wherein, VBATTo output a voltage, VFBThe voltage value of the feedback signal FB is sampled for said voltage,and the ratio of the sampling resistors in the output voltage sampling module is obtained. In the present embodiment, after the constant voltage output VFBIt was 1.2V.
As an implementation manner of the embodiment, the method further comprises 3) turning off the constant-current and constant-voltage control circuit 1 when the charging is full.
Specifically, whether the current flowing through the output tube rate tube M2 drops to a set point is judged based on the current sampling feedback signal PROG, if so, a full charge judgment signal STANDBY is activated, a power supply to ground path of the output tube rate tube M2 is turned off, and charging is stopped; otherwise, the charging state is maintained.
Example two
As shown in fig. 4, the present embodiment provides a linear charging system 01, where the linear charging system 01 includes:
a constant current and voltage control circuit 1, a power input circuit 2, and a battery module 3 according to the first embodiment.
As shown in fig. 4, the constant current and constant voltage control circuit 1 is used to realize constant current and constant voltage control, and further obtain stable output. In this embodiment, the constant current and constant voltage control circuit 1 forms a chip, and in order to improve the flexibility of the constant current and constant voltage control circuit 1, the sampling resistor Rs is arranged outside the chip, and the setting of the output current can be realized by selecting the sampling resistors Rs with different resistance values. The specific structure and connection relationship of the constant current and constant voltage control circuit 1 are described in the first embodiment, and are not described in detail herein.
As shown in fig. 4, the power input circuit 2 is connected to the constant current and constant voltage control circuit 1, and provides an input power VIN for the constant current and constant voltage control circuit.
Specifically, in the present embodiment, the power input circuit 2 includes a voltage source S3 and a first filter capacitor C1, one end of the voltage source S3 is grounded, and the other end outputs the input power VIN; the first filter capacitor C1 is connected in parallel to two ends of the voltage source S3 to filter the input power source VIN. In practical use, the voltage source S3 may be replaced by a rectifying module, and the input power VIN is obtained by converting an ac power through the rectifying module, which is not limited in this embodiment.
As shown in fig. 4, the battery module 3 is connected to the drain of the output power transistor M2, and is configured to receive and store the electric energy output by the constant current and constant voltage control circuit 1.
Specifically, in this embodiment, the battery module 3 includes a battery load 31 and a second filter capacitor C2, the positive electrode of the battery load 31 is connected to the output end of the constant current and constant voltage control circuit 1, and the negative electrode is grounded; the second filter capacitor C2 is connected in parallel to two ends of the battery load 31, and is configured to filter the output voltage of the constant-current and constant-voltage control circuit 1.
As an implementation manner of this embodiment, the linear charging system 01 further includes a charging indication circuit 4, a control terminal of the charging indication circuit 4 is connected to the full charge judgment signal STANDBY, and the charging indication lamp is turned off when the linear charging system 01 stops charging.
Specifically, in this embodiment, the charge indication circuit 4 includes the third resistor R3, the charge indicator D3 and the switch tube N3 that are connected in series in proper order, and in this embodiment, the charge indicator D3 adopts the LED lamp, the switch tube N3 adopts N type transistor, and in actual use, the device that can realize the instruction wantonly, can realize the device of switch all is applicable to the utility model discloses. When fully charged, the charge indicating circuit 4 is turned off, and the charge indicating lamp D3 is turned off.
In order to improve the integration level, in the present embodiment, the switching tube N3 is integrated inside the chip.
To sum up, the utility model provides a linear charging system and constant current and constant voltage control circuit, which comprises a constant current and constant voltage control circuit, a power input circuit for supplying power to the constant current and constant voltage control circuit and a battery module for storing energy; wherein, constant current constant voltage control circuit includes: the grid electrode control module is used for adjusting the grid electrode voltage of the current sampling tube and the output power tube based on a voltage sampling feedback signal and a current sampling feedback signal. The utility model discloses a linear charging system and constant current constant voltage control circuit pass through linear control and establish ties N type adjusting tube impedance on current sampling branch road, and no starting current overshoots, solve linear charging management and have the current when starting and overshoot even by its problem that leads to constantly restarting, and can simplify some circuits; and the output current still keeps the current amplification factor with high precision when the output voltage is lower. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may 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 (11)
1. A constant current and constant voltage control circuit is characterized by at least comprising:
the device comprises a current sampling tube, an output power tube, a voltage following control module, an output voltage sampling module and a grid control module;
the source electrode of the current sampling tube is connected with an input power supply, the grid electrode of the current sampling tube is connected with the output end of the grid electrode control module, the drain electrode of the current sampling tube is connected with the first end of the sampling resistor after passing through the voltage following control module, the second end of the sampling resistor is grounded, and the current sampling tube is used for generating sampling current;
the source electrode of the output power tube is connected with the input power supply, the grid electrode of the output power tube is connected with the output end of the grid electrode control module, and the drain electrode of the output power tube is connected with the output voltage sampling module and used for adjusting output current;
the voltage following control module is connected to the drain electrodes of the current sampling tube and the output power tube and is used for controlling the drain electrode voltage of the current sampling tube to follow the drain electrode voltage of the output power tube, wherein the voltage following control module comprises an operational amplifier and an N-type adjusting tube; the input end of the operational amplifier is respectively connected with the current sampling tube and the drain electrode of the output power tube; the drain electrode of the N-type adjusting tube is connected with the drain electrode of the current sampling tube, the source electrode of the N-type adjusting tube is connected with the first end of the sampling resistor, and the grid electrode of the N-type adjusting tube is connected with the output end of the operational amplifier;
the grid control module is connected with the output voltage sampling module and the first end of the sampling resistor, compares a voltage sampling feedback signal output by the output voltage sampling module with a first calibration voltage, compares a current sampling feedback signal on the sampling resistor with a second calibration voltage, and adjusts the grid voltage of the current sampling tube and the output power tube based on two comparison results, thereby controlling the output voltage value.
2. The constant-current constant-voltage control circuit according to claim 1, characterized in that: the constant-current constant-voltage control circuit further comprises a constant-current calibration point selection module, wherein the constant-current calibration point selection module is connected with the drain electrode of the output power tube, compares the voltage of the drain electrode of the output power tube with a first reference, and outputs a constant-current calibration point selection signal to determine the value of the first calibration voltage.
3. The constant-current constant-voltage control circuit according to claim 2, characterized in that: the constant-current constant-voltage control circuit further comprises a full charge judging module, wherein the full charge judging module is connected with the first end of the sampling resistor, compares the current sampling feedback signal with a second reference and outputs a corresponding full charge judging signal.
4. The constant-current constant-voltage control circuit according to claim 3, characterized in that: the full charge judging module comprises a comparing unit and a NAND logic unit; the input end of the comparison unit is respectively connected with the current sampling feedback signal and the second reference; the input end of the NAND logic unit is respectively connected with the comparison unit and the output end of the constant current calibration point selection module, and the full charge judgment signal takes effect when the drain voltage of the output power tube is greater than the first reference and the current sampling feedback signal is less than the second reference.
5. The constant-current constant-voltage control circuit according to claim 4, wherein: the constant-current constant-voltage control circuit further comprises a full-charge turn-off module, the full-charge turn-off module is connected in series in a power supply to ground passage of the output power tube, and a control end of the full-charge turn-off module is connected with the full-charge judgment signal.
6. The constant-current constant-voltage control circuit according to claim 1, characterized in that: the constant-current constant-voltage control circuit also comprises a substrate selection module, wherein the substrate selection module comprises a first diode and a second diode; the anode of the first diode is connected with the input power supply, and the cathode of the first diode is connected with the current sampling tube and the substrate of the output power tube; and the cathode of the second diode is connected with the cathode of the first diode, and the anode of the second diode is connected with the drain electrode of the output power tube.
7. The constant-current constant-voltage control circuit according to claim 1, characterized in that: the constant-current and constant-voltage control circuit further comprises a reference voltage generation module, wherein the reference voltage generation module receives the input power supply and generates reference voltage and calibration voltage in the constant-current and constant-voltage control circuit based on the input power supply.
8. The constant-current constant-voltage control circuit according to claim 1, characterized in that: the constant-current and constant-voltage control circuit further comprises a pull-up current source, one end of the pull-up current source is connected with the input power supply, and the other end of the pull-up current source is connected with the first end of the sampling resistor.
9. The constant-current constant-voltage control circuit according to claim 1, characterized in that: the constant-current constant-voltage control circuit further comprises a pull-down current source, one end of the pull-down current source is connected with the output end of the grid control module, and the other end of the pull-down current source is grounded.
10. A linear charging system, characterized in that the linear charging system comprises at least:
the constant current and voltage control circuit according to any one of claims 1 to 9, a power input circuit and a battery module;
the power supply input circuit is connected with the constant-current constant-voltage control circuit and provides an input power supply for the constant-current constant-voltage control circuit;
the battery module is connected to the drain electrode of the output power tube and used for receiving and storing the electric energy output by the constant-current constant-voltage control circuit.
11. The linear charging system of claim 10, wherein: the linear charging system further comprises a charging indicating circuit, a control end of the charging indicating circuit is connected with the full charge judging signal, and the charging indicating circuit is turned off when the linear charging system stops charging.
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| CN201920206281.4U CN209844567U (en) | 2019-02-18 | 2019-02-18 | Linear charging system and constant-current and constant-voltage control circuit |
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| CN201920206281.4U CN209844567U (en) | 2019-02-18 | 2019-02-18 | Linear charging system and constant-current and constant-voltage control circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109861329A (en) * | 2019-02-18 | 2019-06-07 | 上海南麟电子股份有限公司 | Linear charging systems, constant-current and constant-voltage control circuit and its voltage follow control method |
| CN112511109A (en) * | 2020-09-25 | 2021-03-16 | 锐迪科创微电子（北京）有限公司 | Power amplifying circuit and wireless transmitting apparatus |
| CN114094660A (en) * | 2021-11-04 | 2022-02-25 | 上海芯飏科技有限公司 | Linear charging system with high-voltage turn-off function |
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2019
- 2019-02-18 CN CN201920206281.4U patent/CN209844567U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109861329A (en) * | 2019-02-18 | 2019-06-07 | 上海南麟电子股份有限公司 | Linear charging systems, constant-current and constant-voltage control circuit and its voltage follow control method |
| CN112511109A (en) * | 2020-09-25 | 2021-03-16 | 锐迪科创微电子（北京）有限公司 | Power amplifying circuit and wireless transmitting apparatus |
| CN112511109B (en) * | 2020-09-25 | 2023-10-27 | 锐迪科创微电子（北京）有限公司 | Power amplifying circuit and wireless transmitting device |
| CN114094660A (en) * | 2021-11-04 | 2022-02-25 | 上海芯飏科技有限公司 | Linear charging system with high-voltage turn-off function |
| CN114094660B (en) * | 2021-11-04 | 2023-04-28 | 上海芯飏科技有限公司 | Linear charging system with high-voltage turn-off function |
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