CN109245522B

CN109245522B - Constant voltage direct current power supply circuit

Info

Publication number: CN109245522B
Application number: CN201810964907.8A
Authority: CN
Inventors: 徐强; 张海丰
Original assignee: Qingdao iTechene Technologies Co ltd
Current assignee: Qingdao iTechene Technologies Co ltd
Priority date: 2018-08-23
Filing date: 2018-08-23
Publication date: 2023-10-03
Anticipated expiration: 2038-08-23
Also published as: CN109245522A

Abstract

The invention belongs to the technical field of constant-voltage direct-current power supply circuits, and particularly relates to a constant-voltage direct-current power supply circuit, which comprises a chip UQ1, a voltage input end Vint, a resistor RV1, a diode DP1, an inductance coil L1, a grounding end 1, a super capacitor C1, a voltage Vcap, a resistor RV4, a diode DV1, a voltage output end Vout, a grounding end 2, a resistor R3, a resistor R4, a capacitor C2 and an electrolytic capacitor C3, wherein when the input voltage Vin is larger than Vout, the output voltage is 4V, when the input voltage Vin is smaller than or equal to Vout, the output voltage is still 4V in a boosting working mode, after the main power supply is cut off, vin is smaller than Vcap and gradually tends to 0, the power supply of the C1 keeps working, when the EN end is set high, the constant-voltage direct-current power supply circuit operates, and when the voltage of the capacitor C1 is discharged to be lower than 0.8V, the constant-voltage direct-current power supply circuit automatically enters a shutdown mode; the output voltage of the voltage output end Vout is adjustable, and the output voltage is controlled by the voltages of the resistor R3, the resistor R4 and the FB end.

Description

Constant voltage direct current power supply circuit

Technical field:

the invention belongs to the technical field of constant-voltage direct-current power supply circuits, relates to a constant-voltage direct-current power supply circuit, is applied to all power supply circuits using batteries or capacitor energy storage devices, and simultaneously provides a new idea for miniaturization of products.

The background technology is as follows:

one DC power supply has two working states, one is in a constant voltage state and works according to the characteristics of the constant voltage power supply; one is in a constant current state, and works according to the characteristics of a constant current power supply. The constant voltage and constant current power supply is a power supply with both constant voltage control components and constant current control components. In general, the chip has a rated operating voltage range, in which the chip can normally operate, and the voltage output range of the energy storage component (farad capacitor or rechargeable battery) is far greater than the operating voltage range of the chip, and the voltage of the energy storage component is far higher than the operating voltage of the chip under the condition of full charge, so that a step-down voltage regulating circuit (Low Dropout Voltage Regulator) or a DC/DC converter with one-level low voltage difference is added between the power output of the energy storage original power supply and the power supply pin of the chip, and the power supply voltage is controlled within the allowable operating voltage range of the chip, namely, the energy storage output voltage is reduced to the operating voltage of the chip. However, when the output voltage of the energy storage element is close to or lower than the chip operating voltage, the power supply cannot drive the chip to operate, that is, the residual electric quantity in the energy storage element is wasted. The national power grid company puts forward the requirement of maintaining 4G communication for at least 1 minute after power failure on the centralized meter reading terminal, so that the product is required to continuously work after the power failure by means of the energy storage device, and according to the characteristic of high 4G communication power consumption, more than 50F of capacitor is required to store electric energy according to conventional design, thus four problems are led out, namely, the energy storage device is high in price, the capacity is larger, and the material cost is higher; secondly, the volume of the energy storage device is large, and the volume of the product is influenced; thirdly, the weight of the product is correspondingly increased; fourth, at the moment of power-on, the capacitor is charged, so that the whole power consumption of the product is larger, and the residual voltage in the capacitor cannot be utilized after power failure. The invention discloses a high-power low-temperature constant-voltage direct-current power supply disclosed in China patent 201621442378.8, which comprises an external power supply access charging module, a battery pack is accessed to the charging module, the battery pack is connected to a closing shunt and a control shunt through a voltage-reducing silicon chain, the voltage-reducing silicon chain is replaced by a direct-current voltage holding circuit, the direct-current voltage holding circuit comprises two voltage-dividing capacitors and two triodes, particularly an E1 end, a collector electrode of a triode VT1 and a first end of a capacitor C1 are connected to a j1 end, a D2 end is connected to an emitter electrode of the triode VT1 and a collector electrode of the triode VT2, and is simultaneously connected to a second end of the capacitor C1 and a first end of the capacitor C2 and is connected to the j2 end, the j3 end and the D1 end, the G1 end is connected to an emitter electrode of the triode VT2, a second end of the capacitor C2 is connected to the j4 end and the F1 end, the E1 end and the G1 end are connected to the E end of the original voltage-reducing silicon chain, the D1 end and the F1 end are connected to the D end and the F end of the original voltage-reducing silicon chain, and the j1 end, the j2 end, the j3 end and the voltage controller are connected to the D1 end and the voltage controller of the triode VT 2; a dc constant voltage conversion circuit disclosed in chinese patent 201610844467.3, comprising: logic control and drive circuits; a voltage generation circuit connected to the logic control and drive circuit; the detection circuit is connected with the logic control and driving circuit, the voltage generating circuit and the power supply; a signal generating circuit connected to the logic control and driving circuit and the voltage generating circuit; and a charge-discharge switch connected to the logic control and drive circuit and the voltage generation circuit; the signal generating circuit is used for converting the previous charge and discharge voltage to generate a first modulation signal; the detection circuit is used for detecting the voltage value of the power supply and the current value of the voltage generation circuit and generating a first logic signal according to the voltage value and the current value; the logic control and drive circuit is used for changing the state of the charge-discharge switch according to the first logic signal and the first modulation signal; the charge-discharge switch comprises a first switch and a second switch which are in different states and is used for controlling the voltage generating circuit to perform charge-discharge operation; the voltage generating circuit is used for performing charge and discharge operations according to the states of the first switch and the second switch and outputting the current charge and discharge voltage for the next charge and discharge operation; the direct current constant voltage circuit module disclosed in the Chinese patent 201610461131.9 is arranged on a main control integrated circuit board and comprises a battery monitoring unit and a storage battery module, wherein the battery monitoring unit and the storage battery module are coupled with a direct current motor through the main control integrated circuit board; the main control integrated circuit board is used for detecting and controlling the flow of the storage battery module so as to keep a constant voltage working area when the storage battery module releases voltage, and when the direct current motor operates, the main control integrated circuit board compensates the voltage of the storage battery module through a micro control unit and a voltage supplementing frequency detection unit so as to enable the storage battery module to reach constant voltage and the direct current motor to reach constant speed, and the main control integrated circuit board controls and displays the residual electric quantity of the storage battery module and controls the direct current motor to stop working in real time when the power of the storage battery module is insufficient or the direct current motor is charged; the constant voltage and constant current automatic switching circuit of the direct current stabilized power supply disclosed in China patent 20132005013. X comprises a direct current stabilized power supply output channel, a direct current stabilized power supply output terminal, a voltage sampling circuit, a current sampling circuit, a voltage comparator, a current comparator, a JK trigger, a constant current and constant voltage switching switch, a constant voltage circuit and a constant current circuit, wherein the output end of the direct current stabilized power supply output channel is electrically connected with the input end of the current sampling circuit and the direct current stabilized power supply output terminal, the output end of the current sampling circuit is electrically connected with the non-inverting input end of the current comparator, the inverting input end of the current comparator is electrically connected with a reference current, the direct current stabilized power supply output terminal is also electrically connected with the input end of the voltage sampling circuit, the output end of the voltage sampling circuit is electrically connected with the in-phase input end of the voltage comparator, the inverting input end of the voltage comparator is electrically connected with a reference voltage, the output end of the current comparator is electrically connected with the J end of the JK trigger, the output end of the voltage comparator is electrically connected with the K end of the JK trigger, the input end of the constant-current constant-voltage switching switch is electrically connected with the Q end of the JK trigger, the input end of the constant-current constant-voltage switching switch is electrically connected with one output end of the constant-current constant-voltage switching switch, the input end of the constant-current circuit is electrically connected with the other output end of the constant-current constant-voltage switching switch, the output end of the constant-current circuit is electrically connected with one input end of the output channel of the direct-current constant-voltage power supply, and the output end of the constant-current constant-voltage power supply is electrically connected with the other input end of the output channel of the direct-current constant-voltage power supply; the circuit related to the patent can not solve the problem of waste of residual electric quantity of energy storage components (such as batteries, capacitors and the like) in the electronic product. Therefore, a constant-voltage direct-current power supply circuit with low cost, small volume and light weight for improving the utilization efficiency of electric energy is developed and designed to realize good social value and economic benefit.

The invention comprises the following steps:

the invention aims to overcome the defects in the prior art, designs a constant-voltage direct-current power supply circuit, reduces the material cost, the volume and the weight of a product, solves the problem of utilizing residual voltage, and simultaneously uses a small-capacity energy storage element.

In order to achieve the above objective, the main structure of the constant voltage dc power supply circuit according to the present invention includes a chip UQ1, a voltage input terminal Vint, a resistor RV1, a diode DP1, an inductor L1, a ground terminal 1, a super capacitor C1, a voltage Vcap, a resistor RV4, a diode DV1, a voltage output terminal Vout, a ground terminal 2, a resistor R3, a resistor R4, a capacitor C2, and an electrolytic capacitor C3; the chip UQ1 is provided with 10 pins, the pin 1 is an EN end, the pin 2 is a VOUT end, the pin 3 is a FB end, the pin 4 is a LBO end, the pin 5 is a GND end, the pin 6 is a VBAT end, the pin 7 is a LBI end, the pin 8 is a PS end, the pin 9 is a SW end, the pin 10 is a PFND end, the voltage input end Vint is respectively connected with the EN end, the VBAT end and the SW end after being connected with the resistor RV1 and the diode DP1 in series, an inductance coil L1 is connected between the voltage input end Vint and the SW end in series, a super capacitor C1 and a capacitor C1 are connected between the ground end 1 and the voltage input end Vint in parallel, the other end of the super capacitor C1 is connected with the voltage Vcap, the ground end 1 is respectively connected with the GND end, the LBI end and the PS end, the resistor RV4 is connected between the ground end 1 and the LBI end in series, the VOUT end is connected with the diode DV1 in series and then is connected with the voltage output end Vout, the PGND end is connected with the ground end 2, a resistor L3 is arranged between the ground end and the FB end and the resistor VOUT 3, and the resistor C2 is connected with the ground capacitor C2 in parallel.

Compared with the prior art, when the input voltage Vin is larger than Vout, the output voltage is 4V (Vout=4V), when the input voltage Vin is smaller than or equal to Vout, the output voltage is still 4V (Vout=4V), after the main power supply is powered off, vin is smaller than Vcap and gradually tends to 0, the C1 power supply keeps working, when the EN terminal is set high, the constant-voltage direct-current power supply circuit operates, and when the capacitor C1 discharges to a voltage lower than 0.8V, the constant-voltage direct-current power supply circuit automatically enters a shutdown mode; the output voltage of the voltage output end Vout is adjustable, and the output voltage is controlled by the voltages of the resistor R3, the resistor R4 and the FB end (the voltages are equal to the voltages at the two ends of the resistor R4); the circuit has the advantages of simple structure, low manufacturing cost, small occupied volume and light self weight, solves the problem of utilizing residual voltage, and can use the energy storage element with small capacity.

Description of the drawings:

fig. 1 is a schematic diagram of the main circuit structure of the present invention.

Fig. 2 is a schematic diagram of a discharge curve of a 50F supercapacitor according to the present invention.

FIG. 3 is a schematic diagram of a discharge curve of a 22F supercapacitor according to the present invention;

fig. 4 is a schematic diagram of a 4V supply voltage output of a 50F supercapacitor in combination with LOD according to the present invention.

Fig. 5 is a schematic diagram of a 4V supply voltage output of the 22F supercapacitor-combined chip UQ1 according to the present invention.

The specific embodiment is as follows:

the invention is further described below by way of examples and with reference to the accompanying drawings.

Examples:

the main structure of the constant voltage direct current power supply circuit related to the embodiment comprises a chip UQ1, a voltage input end Vint, a resistor RV1, a diode DP1, an inductance coil L1, a grounding end 1, a super capacitor C1, a voltage Vcap, a resistor RV4, a diode DV1, a voltage output end Vout, a grounding end 2, a resistor R3, a resistor R4, a capacitor C2 and an electrolytic capacitor C3; the chip UQ1 is provided with 10 pins, the pin 1 is an EN end, the pin 2 is a VOUT end, the pin 3 is a FB end, the pin 4 is a LBO end, the pin 5 is a GND end, the pin 6 is a VBAT end, the pin 7 is a LBI end, the pin 8 is a PS end, the pin 9 is a SW end, the pin 10 is a PFND end, the voltage input end Vint is respectively connected with the EN end, the VBAT end and the SW end after being connected with the resistor RV1 and the diode DP1 in series, an inductance coil L1 is connected between the voltage input end Vint and the SW end in series, a super capacitor C1 and a capacitor C1 are connected between the ground end 1 and the voltage input end Vint in parallel, the other end of the super capacitor C1 is connected with the voltage Vcap, the ground end 1 is respectively connected with the GND end, the LBI end and the PS end, the resistor RV4 is connected between the ground end 1 and the LBI end in series, the VOUT end is connected with the diode DV1 in series and then is connected with the voltage output end Vout, the PGND end is connected with the ground end 2, a resistor L3 is arranged between the ground end and the FB end and the resistor VOUT 3, and the resistor C2 is connected with the ground capacitor C2 in parallel.

The chip UQ1 related to the embodiment is a TPS6102X chip, the power conversion efficiency of the TPS6102X chip is 96%, the current limit value is 1500m A, the input voltage range is 0.9-6.5V, the output voltage is adjustable, the highest output voltage is 5.5V, when the input voltage exceeds the rated output voltage, the output voltage is kept stable, and the overload protection function is provided; the output voltage of the voltage output terminal Vout is constant at 4.0V; the resistor R3 and the resistor R4 are resistors with the concentration of 0.5 percent and less than 100 ppm; the super capacitor C1 and the electrolytic capacitor C3 are ESR capacitors.

The TPS6102X chip related to this embodiment is originally as the power supply solution of three or below alkaline batteries or Ni-Cd, ni-Mh battery powered products, but even if rechargeable Ni-Cd, ni-Mh batteries are used, the repeated charging times are only 500-1000 times, the batteries need to be replaced periodically in the actual application of the centralized meter reading terminal, and the super capacitor has hundreds of thousands of charging and discharging cycles, the TPS6102X chip is used in combination with the super capacitor, the operations of replacing batteries and disposing wastes halfway are avoided, innovating the power failure backup power supply of the centralized meter reading terminal by the national power grid company, changing the original Ni-Mh battery power supply into the super capacitor +tps 6102X mode, ensuring the power failure work, and prolonging the service life of the whole backup power supply.

The output current Iout of the constant voltage direct current power supply circuit related to the embodiment is not less than 0.5A, when the input voltage Vin is greater than Vout, the output voltage is 4V in a step-down working mode, (vout=4v); when the input voltage Vin is less than or equal to Vout, the output voltage is still 4V in a boosted working mode, (Vout=4V), after the main power supply fails, vin is less than Vcap and gradually tends to 0, the power supply of C1 keeps working, when the EN terminal is set high, the constant-voltage direct-current power supply circuit operates, and when the voltage of the capacitor C1 is discharged to be lower than 0.8V, the constant-voltage direct-current power supply circuit automatically enters a shutdown mode; the output voltage of the voltage output end Vout is adjustable, the output voltage is controlled by the voltages of the resistor R3, the resistor R4 and the FB end (the voltages are equal to the voltages at the two ends of the resistor R4), wherein the voltages at the two ends of the resistor R4 are fixed to be 0.5V, the resistance value of the resistor R4 is 100KΩ, vout=4V, and the calculation formula of the relation between the output voltage and the resistor is as follows: r3=r4 (Vout/VFB-1), and r4= K, VFB =0.5v and vout=4v are substituted into the above formula to calculate r3=700 kΩ.

Claims

1. The main structure of the constant-voltage direct-current power supply circuit comprises a chip UQ1, a voltage input end Vint, a resistor RV1, a diode DP1, an inductance coil L1, a grounding end 1, a super capacitor C1, a voltage Vcap, a resistor RV4, a diode DV1, a voltage output end Vout, a grounding end 2, a resistor R3, a resistor R4, a capacitor C2 and an electrolytic capacitor C3; the chip UQ1 is characterized by comprising 10 pins, wherein the pin 1 is an EN end, the pin 2 is a VOUT end, the pin 3 is a FB end, the pin 4 is a LBO end, the pin 5 is a GND end, the pin 6 is a VBAT end, the pin 7 is a LBI end, the pin 8 is a PS end, the pin 9 is a SW end, the pin 10 is a PFND end, the voltage input end Vint is connected with the EN end, the VBAT end and the SW end after being connected in series with a resistor RV1 and a diode DP1, an inductance coil L1 is connected in series between the voltage input end Vint and the SW end, a super capacitor C1 and a capacitor C1 are connected in parallel between the ground end 1 and the voltage input end Vint, the other end of the super capacitor C1 is connected with a voltage Vcap, the ground end 1 is connected with the GND end, the LBI end and the PS end respectively, a resistor RV4 is connected in series between the ground end 1 and the LBI end, the VOUT end is connected with the diode DV1 after being connected in series with the voltage output end, the PGND end is connected with the ground end 2, an inductance coil L1 is connected with the ground end, a resistor Vout 3 is arranged between the ground end and the ground end is connected with the capacitor C2, and the capacitor C3 is connected with the ground end 2 in parallel; the chip UQ1 is a TPS6102X chip, the power conversion efficiency of the TPS6102X chip is 96%, the current limit value is 1500m A, the input voltage range is 0.9-6.5V, the output voltage is adjustable, the highest output voltage is 5.5V, and when the input voltage exceeds the rated output voltage, the output voltage is kept stable, so that the overload protection function is realized; the output voltage of the voltage output terminal Vout is constant at 4.0V; the resistor R3 and the resistor R4 are resistors with the concentration of 0.5 percent and less than 100 ppm; the super capacitor C1 and the electrolytic capacitor C3 are ESR capacitors; when the input voltage Vin is larger than Vout, the output current Iout is in a step-down working mode, and the output voltage is 4V; when the input voltage Vin is less than or equal to Vout, the output voltage is still 4V, vin < Vcap and gradually tends to 0 after the main power supply is in power failure, the C1 power supply keeps working, when the EN terminal is set high, the constant-voltage direct-current power supply circuit operates, and when the capacitor C1 discharges to a voltage lower than 0.8V, the constant-voltage direct-current power supply circuit automatically enters a shutdown mode; the output voltage of the voltage output end Vout is adjustable, the output voltage is controlled by the voltages of the resistor R3, the resistor R4 and the FB end, wherein the voltage at the two ends of the resistor R4 is fixed to be 0.5V, the resistance value of the resistor R4 is 100KΩ, vout=4V, and the calculation formula of the relation between the output voltage and the resistor is as follows:

r3=r4 (Vout/VFB-1), and r4= K, VFB =0.5v and vout=4v are substituted into the above formula to calculate r3=700 kΩ.