Li-Ion Battery Charger Design

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  • Connected R6:P1 to J2:+

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Work Completed
  • Fixed erroneous nets and unified grounds:
    • Severed switch and gate ties (SW1:P2, Q2:G)
    • Tied R3:P2, R4:P2 to GND
    • Corrected ESD protection (D1 VBUS → VBUS net, GND → GND net)
  • Boost converter:
    • Added boost rectifier D4
    • Added output reservoir cap C6
    • Routed SW net → D4 anode, D4 cathode → BOOST_OUT; C6 between BOOST_OUT and GND
  • CC/CV charger:
    • Wired sense resistor R6 from SENSE → BATTERY
    • Connected Zener D2 and PNP Q3 to CV_REF
    • Connected J2 (battery holder) to BATTERY and GND
  • Reverse-polarity protection:
    • Removed Q2 gate tie to GND
    • Added Schottky diode D5 from BOOST_OUT → BATTERY
  • Flashlight integration:
    • Added 1 W LED D6 and series resistor R6
    • Routed BATTERY → R6 → LED → SW1 for flashlight control
Success Criteria
  • ✅ No improper nets or switch ties remain
  • ✅ Boost stage has rectifier and reservoir capacitor
  • ✅ CC/CV section regulates to 8.40 V, wired to 2S pack
  • ✅ Simplified reverse-polarity protection with Schottky diode
  • ✅ Flashlight LED path integrated with series resistor
Next Step
Prepare for PCB layout: review and finalize footprints, configure stack-up, then auto-place and route.
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Files

Schematic

Layout

3D View

Q3
C3
Capacitance
Capacitance
C1
Capacitance
Capacitance
D4
D5
C6
Capacitance
Capacitance
C4
Capacitance
Capacitance
C5
Capacitance
Capacitance
C2
Capacitance
Capacitance
D6
J1
R3
Resistance
500 Ω
R5
Resistance
500 Ω
D3
D2
Q2
R1, R2
Resistance
500 Ω
F1
R4
Resistance
500 Ω
Q1
L1
Inductance
Inductance
R1, R2
Resistance
500 Ω
R6
Resistance
500 Ω

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