I'm designing a small solar charger with these characteristics:
- Voc = 5,65 V
- Vmp = 4,25 V (Voc -25% approx.)
- Isc = 250 mA
IC CHARGER CONTROLLER
STMicroelectronics SPV1040 High efficiency solar battery charger with embedded MPPT
- Type Li-Po (Model LP804367, FULLWAT)
- Nominal Voltage 3.7 V
- Nominal Capacity 2400 mAh
- Standard Charge Current 480 mA
- Max Charge Current 4800 mA
- Charge cut-off Voltage 4.20+/-0.05 V
- Discharge cut-off Voltage 2.75 V
When I have entered the characteristics of the solar panel in the eDesignSuite tool, I have introduced as open circuit voltage the value Voc = 5.2 V which is the maximum input voltage allowed by the IC SPV1040T. However, the Voc value of the solar panel used is 5.65 V, so I thought of using a zener diode in parallel with the capacitor Cin to not exceed this the maximum voltage allowed at the IC input (5.2 V).
- Is this correct or is there a better solution than using a zener diode to clamp the input voltage?
- Could the zener diode decrease to the efficiency of the MPPT algorithm?
- If using a diode zener is a feasible solution, could this zener diode be used? (1SMA5918BT3G)