SLUAAO7 March 2023 BQ24640 , BQ25173 , BQ25713 , BQ25798
This application note's supercap charging designs can be easily scaled to fit larger or higher voltage supercaps by changing the charge voltages and or charge currents. The key concern, and charge time variable, is how the charging circuit manages its high power losses and heat dissipation until the supercap voltage reaches a manageable voltage level. Table 3-1 compares the options,
Design | Input Power Voltage | Capacitance | Charge Current | Charge Time | Other features |
---|---|---|---|---|---|
BQ25173 linear charger | > V(REG) | Low | < 1 A | long | Small size |
BQ24640 buck charger | > V(REG) | Med-High | >1 A but < 10 A | Short - medium | |
BQ25798 b-b charger plus TPS25221 switch | <or > V(REG) | Med-High | >1 A but <5 A | medium | LiIon or supercap charging with host software |
BQ25713/30 b-b controller | <or > V(REG) | High | >2 A but < 20 A | short |