UPS Charger Design

wilsonkang

wilsonkang

Help me think the UPS charger.
the spec :
-Input voltage: 240V + - 10% -OUTPUT Voltage: 24V DC -Batt voltage : 27.6V for floting charge. -Charging current : Max 0.8A
-Auto switch to boost charge, once battery full auto switch to floting charge. Output signal for normal charging and boost charge indicator.
can use LM723
-lead acid battery 4 pcs with 7,2AH
when normal AC power, charge the battery and continue output 24V when power fail, battery discharge and continue output 24V.
-circuit design must including under/over circuit protection, surge proetion and battery wrong polarity protection.

flux

No design changes were made; execution is unavailable because the account has no remaining ACUs.
Remaining work:
  • Confirm the four 7.2 Ah batteries are 6 V units in series (24 V nominal). A 27.6 V float voltage implies a 12-cell lead-acid pack.
  • Define boost-charge voltage (typically around 28.8 V at 25°C) and temperature compensation.
  • Design the isolated 240 VAC front end, LM723-based CC/CV charger limited to 0.8 A, automatic boost/float control, seamless 24 V backup path, status outputs, and protections for surge, OVP/UVLO/OCP, deep discharge, and reversed battery.
  • Verify transformer/power-stage ratings, thermal margins, fault behavior, and mains safety spacing.
Because this involves lethal 240 VAC and high battery fault current, the final implementation must use reinforced isolation, correctly rated fusing/MOV protection, and qualified safety review.
Confirm battery arrangement
Set boost voltage
Define operating details
Create charger requirements
Choose charger architecture
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