CN3767 circuit lead-acid battery charger

Schematic CN3767 circuit lead-acid battery charger

CN3767 circuit lead-acid battery charger, CN3767 is an integrated circuit for managing the charging of a 4A, 12V lead-acid battery with maximum power point tracking function for solar panels, Lead-acid battery charging, Uninterruptible power supply, Backup battery application, Portable industrial and medical instruments, Standalone battery charger.


  1. 1Maximum charging current is 4A.
  2. Suitable for 1 piece of 12V lead-acid battery.
  3. Input voltage is 15.2V~28V


  1. It is recommended to waterproof the circuit board in a damp and rainy environment by coating both sides of the circuit board with 704 silicone rubber or placing it in a waterproof box.
  2. Do not reverse the positive and negative terminals, as it may cause permanent damage to the product.
  3. As shown in the diagram, L1 is a 47uh toroidal inductor and R2 is a 30 milliohm copper wire resistor.

Schematic CN3767 circuit lead-acid battery charger


CN3767 is an integrated circuit for managing the charging of a 4A, 12V lead-acid battery with maximum power point tracking function for solar panels.

CN3767 is a PWM buck mode 12V lead-acid battery charging IC, which independently manages the automatic charging of lead-acid batteries. It has the advantages of small package size, fewer peripheral components, and simple use.

CN3767 has trickle charge, constant current, overcharge, and float charge modes, which are very suitable for charging 12V lead-acid batteries. In the overcharge and float charge modes, the typical charging voltages are 14.8V and 13.55V respectively; in the constant current charging mode, the charging current is set by an external resistor.

When powered by a solar panel, the internal circuit can automatically track the maximum power point of the solar panel, allowing users to maximize the output power of the solar panel without having to consider the worst-case scenario, making it ideal for applications powered by solar panels.

If the battery voltage drops below 75% of the set overcharge voltage, CN3767 will trickle charge the battery with 17.5% of the set constant current charging current. In the overcharge stage, the charging current gradually decreases, and when the charging current drops to 38% of the constant current charging current, CN3767 enters float charge mode. In float charge mode, if the battery voltage drops to 83.95% of the set overcharge voltage, a new charging cycle will automatically begin.

When the input power is disconnected or the input voltage is lower than the battery voltage, CN3767 will automatically enter a low power consumption sleep mode. Other features include input low voltage lockout, battery terminal overvoltage protection, and charging status indication.

CN3767 uses a 10-pin SSOP package.

Pcb 3D


  • Lead-acid battery charging
  • Uninterruptible power supply
  • Backup battery application
  • Portable industrial and medical instruments
  • Standalone battery charger


  • Maximum power point tracking function for solar panels
  • Wide input voltage range: 6.6V to 30V
  • Complete charging management for 12V lead-acid batteries
  • Overcharge and float charge voltages are 14.8V and 13.55V respectively
  • Charging current up to 4A
  • PWM switch frequency: 300KHz
  • Constant current charging current set by external resistor
  • Trickle charge for deeply discharged batteries
  • Automatic recharging function
  • Dual status indication
  • Soft start function
  • Battery terminal overvoltage protection
  • Operating environment temperature: -40 °C to +85 °C
  • 10-pin SSOP package
  • Lead-free, halogen-free elements, RoHS compliant
Cn3767 Circuit Lead-Acid Battery Charger Curve

BOM CN3767 circuit lead-acid battery charger

Value Name Description Quantity
220nF C1 C0603 – SMD capacitor 1
100nF C2,C6,C7 C0603 – SMD capacitor 3
1000uF/25V C3 Electrolytic capacitor 1
470uF 35V C4,C5 Electrolytic capacitor 2
120Ω (121 or 1200) R1 R0603 – SMD resistor 1
0.03Ω (R030) R2 R2512 – SMD resistor 1
143kΩ (1433) R3 R0603 – SMD resistor 1
10kΩ (103 or 1002) R4 R0603 – SMD resistor 1
1.2kΩ (122 or 1201) R5 R0603 – SMD resistor 1
AOD4185 Q1 40V 40A 15 mΩ@10V,20A 3V@250uA P Channel TO-252(DPAK) MOSFET 1
SS54 D1 40V 5A SMB Schottky Barrier Diodes (SBD) 1
Red LED1 LED0603 – SMD LED red 1
Green LED2 LED0603 – SMD LED green 1
CN3767 U1 SSOP-10-150mil Battery Management ICs 1
KF128-5.08-2P U2,U3 Screw terminal 5.08 mm 2 pin 2
47uh L1 CR-15 Toroidal inductor 1

Download files, links, and notes

Pcb 3D

Download PCB in Gerber, PDF, PNG and SVG




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About the author blog author. Electronics technician for the technical school of Brasilia - Brazil. Interested in electronics, circuits and technology in general.

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