Summary of the invention
The present invention is to solve the above problems of the prior art, propose a kind of constant-current charging circuit using floating ground formula.
In order to solve the above technical problems, technical solution proposed by the present invention is to design a kind of constant-current charge using floating ground formula
Circuit comprising：The input anode and input ground of connection DC power supply, the output cathode of connection battery pack and floating ground are connected to
Afterflow energy-storage module between output cathode and floating ground is sequentially connected in series in the inductance element and electronic cutting floatingly between input ground
It closes, the PWM control module of control electronic switch on-off.
Charging circuit further includes：It acquires the output cathode voltage and feeds back surveyed output voltage to PWM control module
Voltage sample module.
Current sampling module is concatenated between the electronic switch and input ground, which will survey output electric current
Feed back to the PWM control module.
The afterflow energy-storage module includes：It is connected in parallel on the 6th capacitor inputted between anode and the floating ground, the 7th
Capacitor, the positive third diode being serially connected between inductance element and electronic switch tie point and the input anode.
The PWM control module includes pwm chip and its peripheral circuit.
The voltage sample module has comparator and three terminal regulator, concatenates the 7th between the input anode and floating ground
The inverting input terminal of the contact connection comparator of resistance and the 8th resistance, the 7th resistance and the 8th resistance, input anode with
Twelfth resistor, the 9th resistance and the tenth resistance, the contact connection comparator of the 9th resistance and the tenth resistance are concatenated between floating ground
Noninverting input, twelfth resistor connects the cathode and control electrode of three terminal regulator, three-terminal voltage-stabilizing with the contact of the 9th resistance
The cathode of device connects floating ground, and the inverting input terminal of comparator connects the output of comparator by concatenated 6th resistance and the 5th capacitor
The output end at end, comparator feeds back surveyed output voltage to pwm chip by the 5th resistance.
The current sampling module includes：It is serially connected in the electronic switch and inputs the 3rd resistor between ground, third electricity
The contact of resistance and electronic switch surveys output electric current, the ground connection of pwm chip to pwm chip feedback by the 4th resistance
Foot connection input ground.
The inductance element uses transformer, the primary side winding of the transformer be serially connected in it is described floatingly with electronic switch it
Between, the third diode forward is serially connected between primary side winding and electronic switch tie point and input anode；The change
Depressor vice-side winding one end connects the input ground, the other end is powered to the PWM control module.
The other end of the transformer secondary winding connects the anode of the second diode, and the cathode of the second diode is to described
Pwm chip powers and connects the cathode first resistor of the first zener diode and one end of the second capacitor, first resistor
The other end connect input anode, the other end of the second capacitor is with connecting the input.
First capacitor is connected between the input anode and input ground.
Compared with prior art, the present invention is using the frame mode for floating ground, in conjunction with common topological circuit, to multiple series connection
Battery carry out constant-current charge, effectively improve the voltage range and charge efficiency of charging circuit, practical controllability is good；
The present invention has the advantages that output short circuit protection and overcurrent protection are sensitive, and after output short-circuit or overload, circuit is completely in sky
Load state makes circuit be in most energy-efficient state always；It can be achieved using the present invention to 2 sections to the charging of 32 batteries constant currents,
When number of batteries variation, as long as the voltage of adjustment input, the optimum state worked in so as to circuit.
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is described in further detail.It should be appreciated that specific embodiment described herein is used only for explaining the present invention, not
For limiting the present invention.
Referring to functional block diagram shown in fig. 1, floating ground formula constant-current charging circuit that the present invention discloses it include：Connect direct current
The input anode and input ground in source, the output cathode of connection battery pack and floating ground, be connected to it is continuous between output cathode and floating ground
Stream energy-storage module is sequentially connected in series in the inductance element and electronic switch Q1, control electronic switch on-off floatingly between input ground
PWM control module.
The present invention is using the frame mode for floating ground, in conjunction with common topological circuit, to improve the range of battery operating voltage,
And the processing mode on floating ground is very ingenious, floating ground is realized using the energy storage of capacitor, the benchmark of circuit is with input power
Anode determines, the height of voltage determines the current potential on floating ground, it may also be said to is worked in a manner of negative pressure；Due to be with
On the basis of positive polarity, so current sampling can only be sampled in the anode of power supply, electricity is done with an independent comparator
Stream sampling can equally be accomplished precisely, to improve efficiency.In addition output protection circuit, makes two part circuit perfect combinations, to mention
The high reliability of circuit.
Referring to Fig. 2 shows preferred embodiment circuit diagram, main circuit with pwm chip U1 come carry out PWM generation open
OFF signal and current constant control, 4 feet of U1 and the composition PWM driving of 8 feet, by the conducting and cut-off of Q1, input energy is passed by T1
It is defeated to arrive rear class, and by the isolation of Q1, keep output ground potential different from ground potential is inputted, output ground becomes floating ground.It presses floatingly
Difference is related to the conducting degree of Q1.Q1, R3 constitute pressure limiting circuit, and T1 is allowed to be inputted and exported energy by the on-off of Q1
Conversion, R3 limit maximum output electric current.
In the preferred embodiment, charging circuit further includes：Acquire the output cathode voltage and anti-to PWM control module
Present the voltage sample module of surveyed output voltage.Current sampling module is concatenated between the electronic switch and input ground, the electric current
Sampling module, which will be surveyed, exports current feedback to the PWM control module.
Referring to Fig. 2 shows preferred embodiment circuit diagram, the afterflow energy-storage module includes：It is connected in parallel on the input just
The 6th capacitor C6, the 7th capacitor C7 between pole and the floating ground, forward direction are serially connected in inductance element and electronic switch Q1 tie point
With the third diode D3 between the input anode.C6, C7, D3 form the afterflow power supply circuit of afterflow energy storage, filtering.C6 and
The main work function of C7 be by because topological circuit in switch state caused by dynamic effects eliminate, make floatingly in steady
Fixed working condition.
The PWM control module includes pwm chip U1 and its peripheral circuit.
Referring to Fig. 2 shows preferred embodiment circuit diagram, the voltage sample module have comparator (U2A) and three ends
Voltage-stablizer U3, concatenates the 7th resistance R7 and the 8th resistance R8, the 7th resistance and the 8th resistance between the input anode and floating ground
Contact connection comparator inverting input terminal, concatenation twelfth resistor R12, the 9th resistance between input anode and floating ground
The noninverting input of the contact connection comparator of R9 and the tenth resistance R10, the 9th resistance and the tenth resistance, twelfth resistor and the
The cathode and control electrode of the contact connection three terminal regulator of nine resistance, the anode of three terminal regulator connect floating ground, the reverse phase of comparator
Input terminal connects the output end of comparator by concatenated 6th resistance R6 and the 5th capacitor C5, and the output end of comparator passes through the 5th
Resistance R5 feeds back surveyed output voltage to pwm chip U1.Since this charging circuit is on the basis of anode, so sampling electricity
Road is necessarily in anode, and when input voltage is high, the raising of meeting simultaneously floatingly, because being floatingly a variable, it can be with input
The variation of voltage and change.It is to provide a perseverance in circuit by R12, U3, R9, R10 to realize the constant of output voltage
Fixed datum mark, and R7 is adjusted compared with the voltage sampling signal after R8 partial pressure carries out voltage with datum mark by U2A comparator
The FB voltage for saving pwm chip U1, so as to adjust the pulsewidth of Q1, to achieve the purpose that output constant current.
Referring to Fig. 2 shows preferred embodiment circuit diagram, the current sampling module includes：It is serially connected in the electronic cutting
It closes Q1 and inputs the 3rd resistor R3 between ground, the contact of 3rd resistor and electronic switch is controlled by the 4th resistance R4 to PWM
Chip U1 feedback surveys output electric current, the grounding leg connection input ground of pwm chip.R3 is current-limiting resistance, is concatenated by Q1
In input between floating ground, when Q1 is connected, and output is because of battery charging, load is increased, and is added at this time by the electric current of Q1 and R3
Greatly, pressure difference can be generated at the both ends R3, this pressure difference is transferred to the CS foot of U1 by R4 and C3, adjusts Q1 by the height of CS current potential
Pulsewidth, to achieve the purpose that output constant current.When R3 flows through excessive in electric current, potential difference on R3 is caused to be higher than U1 setting
When CS protects voltage, U1 closes the output of 4 foot GATA waveforms, with making input completely isolated between floating ground, power supply overcurrent protection.Overcurrent
The size of protection electricity depends on the size of R3 resistance value.
The inductance element uses transformer T1, the primary side winding of the transformer be serially connected in it is described floatinglyly and electronic switch
Between Q1, the third diode（D3）Forward direction is serially connected in primary side winding and electronic switch（Q1）Tie point and input anode
Between；Transformer secondary winding one end connects the input ground, the other end is powered to the PWM control module.The change
The other end of depressor T1 vice-side winding connects the anode of the second diode D2, and the cathode of the second diode controls core to the PWM
Piece U1 powers and connects one end of the cathode first resistor R1 and the second capacitor C2 of the first zener diode ZD1, first resistor
The other end connect input anode, the other end of the second capacitor is with connecting the input.The input anode and input ground
Between connect first capacitor C1.C1 can be filtered input dc power.When output short-circuit, transformer T1 is in short for a long time
Line state, feedback of the U1 because cannot get T1 are worked normally for U1 without power supply, so Q1 can be constantly in off state, are caused
Completely isolated between input ground and floating ground, power input is in light condition.When output short-circuit is eliminated, U1 restarting passes through
PWM switchs drive control Q1, makes to generate pressure difference with input floatingly, to maintain the constant current output of output.
Referring to Fig. 2, input anode also concatenates fuse F1, shields to charging circuit.
Above embodiments are by way of example only, non-to provide constraints.It is any without departing from the application spirit and scope, and to it
The equivalent modifications or change of progress, shall be included in the scope of claims of this application.