As we saw in the previous design schematic of the single‑board system, dual input sources are implemented using the LTC4416
The LTC4416 creates seamless switching between two sources with a very low voltage drop, by reducing the power loss.
By controlling the external P-channel MOSFETs so they act like ideal diodes, this device significantly reduces conduction losses, thereby improving overall system efficiency and reliability.
The system operates in a way where the primary source is selected when its voltage exceeds a programmed threshold. When the primary input drops below the fail voltage, the controller seamlessly transitions to the secondary source.
The LTC4416 can operate in six different modes, depending on how the E1 and E2 pins are set. Each mode controls how the chip chooses between two power sources.
In this setup, the selected mode is V1 > V2, where E1 is set to “Sense” and E2 is set to 0. This means the chip will always give priority to the V1 input.
- V1 accepts a wide input range of 15 V to 35 V, making it the main power source.
- V2 is the solar panel input with a range of 3.6 V to 15 V, acting as the backup power.
When V1 is 15 V or higher, the LTC4416 selects V1 as the primary power source and turns off V2 because V1 is greater.
If V1 drops to 13.4 V, the system automatically switches to V2, making the solar panel the main supply as long as its voltage is within the valid 3.6 V to 15 V range. This continues until V1 rises again.
The restore point—when the system switches back to V1—is set to 15 V.
The failover and restore behavior can be adjusted by changing the resistor values R1, R2, and R3 using formulas from the datasheet.
Once V1 is identified and selected, V2 can be chosen as the backup source. The system will always switch to whichever source has the higher valid voltage, so restoration to V1 will not happen if V2 remains higher than V1.
The board (Figure 3) receives power from two inputs, V1 and V2, which are used to charge the battery and power the load. If the primary power source fails, the solar panel takes over during high sunlight intensity and provides power to the load while charging the battery. At night or when sunlight intensity is weak and the solar panel voltage drops, the system automatically detects this and switches to battery power to keep the load running.
Related Article:
How Does the Smart Power Bank’s Design Manage Multiple Power Sources?
Why Choose a Single‑Board Smart Power Bank for Your Next Project?
Applicable Part Number
| DigiKey Part Number | Manufacturer Part Number |
|---|---|
| 505-LTC3115EDHD-1#PBF-ND | LTC3115EDHD-1#PBF |
| 505-LTC3115EDHD-1#TRPBFTR-ND,505-LTC3115EDHD-1#TRPBFCT-ND,505-LTC3115EDHD-1#TRPBFDKR-ND | LTC3115EDHD-1#TRPBF |
| LTC3115EFE-1#TRPBFTR-ND,LTC3115EFE-1#TRPBFCT-ND,LTC3115EFE-1#TRPBFDKR-ND | LTC3115EFE-1#TRPBF |
| 505-LTC3115EFE-1#PBF-ND | LTC3115EFE-1#PBF |
| 505-LTC3115IDHD-1#TRPBFTR-ND,505-LTC3115IDHD-1#TRPBFCT-ND,505-LTC3115IDHD-1#TRPBFDKR-ND | LTC3115IDHD-1#TRPBF |
| 505-LTC3115IDHD-1#PBF-ND | LTC3115IDHD-1#PBF |
| 505-LTC3115IFE-1#PBF-ND | LTC3115IFE-1#PBF |
| 505-LTC3115EDHD-2#PBF-ND | LTC3115EDHD-2#PBF |
| 505-LTC3115EFE-2#PBF-ND | LTC3115EFE-2#PBF |
| 505-LTC3115IFE-1#TRPBFTR-ND,505-LTC3115IFE-1#TRPBFCT-ND,505-LTC3115IFE-1#TRPBFDKR-ND | LTC3115IFE-1#TRPBF |
| LTC3115IFE-2#PBF-ND | LTC3115IFE-2#PBF |
| 505-LTC3115HFE-1#PBF-ND | LTC3115HFE-1#PBF |
| 505-LTC3115IDHD-2#PBF-ND | LTC3115IDHD-2#PBF |
| 161-LTC3115MPFE-1#PBF-ND | LTC3115MPFE-1#PBF |
| LTC3115MPFE-2#PBF-ND | LTC3115MPFE-2#PBF |
| 505-LTC3115EDHD-2#TRPBFTR-ND | LTC3115EDHD-2#TRPBF |
| 505-LTC3115HFE-2#PBF-ND | LTC3115HFE-2#PBF |
| 161-LTC3115IDHD-1#WPBF-ND | LTC3115IDHD-1#WPBF |
| 505-LTC3115EFE-2#TRPBFTR-ND | LTC3115EFE-2#TRPBF |
| 161-LTC3115IDHD-1#WTRPBFTR-ND | LTC3115IDHD-1#WTRPBF |
| LTC3115IFE-2#TRPBF-ND | LTC3115IFE-2#TRPBF |
| LTC3115HFE-1#TRPBF-ND | LTC3115HFE-1#TRPBF |
| LTC3115HFE-2#TRPBF-ND | LTC3115HFE-2#TRPBF |
| LTC3115IDHD-2#TRPBF-ND | LTC3115IDHD-2#TRPBF |
| LTC3115MPFE-1#TRPBF-ND | LTC3115MPFE-1#TRPBF |
| 505-LTC4162EUFD-LAD#TRPBFTR-ND,505-LTC4162EUFD-LAD#TRPBFCT-ND,505-LTC4162EUFD-LAD#TRPBFDKR-ND | LTC4162EUFD-LAD#TRPBF |
| 505-LTC4162EUFD-FAD#PBF-ND | LTC4162EUFD-FAD#PBF |
| 505-LTC4162EUFD-LAD#PBF-ND | LTC4162EUFD-LAD#PBF |
| 505-LTC4162EUFD-L42#TRPBFTR-ND,505-LTC4162EUFD-L42#TRPBFCT-ND,505-LTC4162EUFD-L42#TRPBFDKR-ND | LTC4162EUFD-L42#TRPBF |
| 505-LTC4162EUFD-SAD#PBF-ND | LTC4162EUFD-SAD#PBF |
| 505-LTC4162EUFD-SADM#PBF-ND | LTC4162EUFD-SADM#PBF |
| 505-LTC4162EUFD-LADM#PBF-ND | LTC4162EUFD-LADM#PBF |
| 505-LTC4162IUFD-FAD#PBF-ND | LTC4162IUFD-FAD#PBF |
| 505-LTC4162IUFD-SADM#PBF-ND | LTC4162IUFD-SADM#PBF |
| 505-LTC4162IUFD-LAD#PBF-ND | LTC4162IUFD-LAD#PBF |
| 505-LTC4162EUFD-L42#PBF-ND | LTC4162EUFD-L42#PBF |
| 505-LTC4162EUFD-L42M#PBF-ND | LTC4162EUFD-L42M#PBF |
| 505-LTC4162EUFD-L41#PBF-ND | LTC4162EUFD-L41#PBF |
| LTC4162EUFD-SSTM#PBF-ND | LTC4162EUFD-SSTM#PBF |
| LTC4162IUFD-FADM#PBF-ND | LTC4162IUFD-FADM#PBF |
| LTC4162IUFD-SSTM#PBF-ND | LTC4162IUFD-SSTM#PBF |
| LTC4162EUFD-L40#PBF-ND | LTC4162EUFD-L40#PBF |
| LTC4162EUFD-L40M#PBF-ND | LTC4162EUFD-L40M#PBF |
| LTC4162EUFD-FFSM#PBF-ND | LTC4162EUFD-FFSM#PBF |
| LTC4162EUFD-L41M#PBF-ND | LTC4162EUFD-L41M#PBF |
| 505-LTC4162EUFD-FSTM#PBF-ND | LTC4162EUFD-FSTM#PBF |
| LTC4162EUFD-FST#PBF-ND | LTC4162EUFD-FST#PBF |
| LTC4162EUFD-FFS#PBF-ND | LTC4162EUFD-FFS#PBF |
| LTC4162IUFD-SST#PBF-ND | LTC4162IUFD-SST#PBF |
| 505-LTC4162IUFD-L42#PBF-ND | LTC4162IUFD-L42#PBF |
| LTC4162IUFD-L40#PBF-ND | LTC4162IUFD-L40#PBF |
| LTC4162IUFD-L40M#PBF-ND | LTC4162IUFD-L40M#PBF |
| LTC4162IUFD-FFSM#PBF-ND | LTC4162IUFD-FFSM#PBF |
| LTC4162IUFD-L41M#PBF-ND | LTC4162IUFD-L41M#PBF |
| 505-LTC4162IUFD-L41#PBF-ND | LTC4162IUFD-L41#PBF |
| LTC4162IUFD-FSTM#PBF-ND | LTC4162IUFD-FSTM#PBF |
| 505-LTC4162IUFD-L42M#PBF-ND | LTC4162IUFD-L42M#PBF |
| LTC4162IUFD-FFS#PBF-ND | LTC4162IUFD-FFS#PBF |
| 505-LTC4162IUFD-LAD#TRPBFTR-ND | LTC4162IUFD-LAD#TRPBF |
| 505-LTC4162EUFD-FADM#TRPBFTR-ND,505-LTC4162EUFD-FADM#TRPBFCT-ND,505-LTC4162EUFD-FADM#TRPBFDKR-ND | LTC4162EUFD-FADM#TRPBF |
| 505-LTC4162IUFD-SAD#PBF-ND | LTC4162IUFD-SAD#PBF |
| 505-LTC4162IUFD-LADM#PBF-ND | LTC4162IUFD-LADM#PBF |
| LTC4162IUFD-FST#PBF-ND | LTC4162IUFD-FST#PBF |
| LTC4162EUFD-FADM#PBF-ND | LTC4162EUFD-FADM#PBF |
| LTC4162EUFD-SST#PBF-ND | LTC4162EUFD-SST#PBF |
| LTC4162EUFD-FAD#TRPBF-ND | LTC4162EUFD-FAD#TRPBF |
| LTC4162EUFD-FFS#TRPBF-ND | LTC4162EUFD-FFS#TRPBF |
| LTC4162EUFD-FFSM#TRPBF-ND | LTC4162EUFD-FFSM#TRPBF |
| LTC4162EUFD-FST#TRPBF-ND | LTC4162EUFD-FST#TRPBF |
| LTC4162EUFD-FSTM#TRPBF-ND | LTC4162EUFD-FSTM#TRPBF |
| LTC4162EUFD-L40#TRPBF-ND | LTC4162EUFD-L40#TRPBF |
| LTC4162EUFD-L40M#TRPBF-ND | LTC4162EUFD-L40M#TRPBF |
| LTC4162EUFD-L41#TRPBF-ND | LTC4162EUFD-L41#TRPBF |
| LTC4162EUFD-L41M#TRPBF-ND | LTC4162EUFD-L41M#TRPBF |
| LTC4162EUFD-L42M#TRPBF-ND | LTC4162EUFD-L42M#TRPBF |
| LTC4162EUFD-LADM#TRPBF-ND | LTC4162EUFD-LADM#TRPBF |
| LTC4162EUFD-SAD#TRPBF-ND | LTC4162EUFD-SAD#TRPBF |
| LTC4162EUFD-SADM#TRPBF-ND | LTC4162EUFD-SADM#TRPBF |
| LTC4162EUFD-SST#TRPBF-ND | LTC4162EUFD-SST#TRPBF |
| LTC4162EUFD-SSTM#TRPBF-ND | LTC4162EUFD-SSTM#TRPBF |
| LTC4162IUFD-FAD#TRPBF-ND | LTC4162IUFD-FAD#TRPBF |
| LTC4162IUFD-FADM#TRPBF-ND | LTC4162IUFD-FADM#TRPBF |
| LTC4162IUFD-FFS#TRPBF-ND | LTC4162IUFD-FFS#TRPBF |
| LTC4162IUFD-FFSM#TRPBF-ND | LTC4162IUFD-FFSM#TRPBF |
| LTC4162IUFD-FST#TRPBF-ND | LTC4162IUFD-FST#TRPBF |
| LTC4162IUFD-FSTM#TRPBF-ND | LTC4162IUFD-FSTM#TRPBF |
| LTC4162IUFD-L40#TRPBF-ND | LTC4162IUFD-L40#TRPBF |
| LTC4162IUFD-L40M#TRPBF-ND | LTC4162IUFD-L40M#TRPBF |
| LTC4162IUFD-L41#TRPBF-ND | LTC4162IUFD-L41#TRPBF |
| LTC4162IUFD-L41M#TRPBF-ND | LTC4162IUFD-L41M#TRPBF |
| LTC4162IUFD-L42#TRPBF-ND | LTC4162IUFD-L42#TRPBF |
| LTC4162IUFD-L42M#TRPBF-ND | LTC4162IUFD-L42M#TRPBF |
| LTC4162IUFD-LADM#TRPBF-ND | LTC4162IUFD-LADM#TRPBF |
| LTC4162IUFD-SAD#TRPBF-ND | LTC4162IUFD-SAD#TRPBF |
| LTC4162IUFD-SADM#TRPBF-ND | LTC4162IUFD-SADM#TRPBF |
| LTC4162IUFD-SST#TRPBF-ND | LTC4162IUFD-SST#TRPBF |
| LTC4162IUFD-SSTM#TRPBF-ND | LTC4162IUFD-SSTM#TRPBF |
| 505-LTC4416EMS-1#PBF-ND | LTC4416EMS-1#PBF |
| 505-LTC4416EMS#TRPBFTR-ND,505-LTC4416EMS#TRPBFCT-ND,505-LTC4416EMS#TRPBFDKR-ND | LTC4416EMS#TRPBF |
| 505-LTC4416EMS#PBF-ND | LTC4416EMS#PBF |
| 505-LTC4416IMS#PBF-ND | LTC4416IMS#PBF |
| 505-LTC4416IMS-1#PBF-ND | LTC4416IMS-1#PBF |
| 505-LTC4416IMS#TRPBFTR-ND,505-LTC4416IMS#TRPBFCT-ND,505-LTC4416IMS#TRPBFDKR-ND | LTC4416IMS#TRPBF |
| LTC4416EMS-1#TRPBFTR-ND,LTC4416EMS-1#TRPBFCT-ND,LTC4416EMS-1#TRPBFDKR-ND | LTC4416EMS-1#TRPBF |
| 505-LTC4416IMS-1#TRPBFTR-ND | LTC4416IMS-1#TRPBF |
| 161-LTC4416IMS-1-ND | LTC4416IMS-1 |