When CPM adopts distributed architecture, each module only needs to unlock one door, so 1s supercapacitor can be used. Below is the design for 1s supercapacitor.

• Buck charge + Boost Discharge

Taking a 1s, 2.7V, 25F supercapacitor as an example, Figure 4-9 is the recommend system block. LM5190-Q1 is a buck charger and LM5152-Q1 is a boost controller used to discharge. The minimum operating voltage of LM5152-Q1 is 3.8V. When the bias voltage is greater than 3.8V, the minimum input voltage is 0.8V. Therefore, an additional boost converter TPS61299-Q1 with low-voltage startup is required to bias LM5152-Q1. TPS61299-Q1 has only 95nA Iq, which hardly consumes the energy of the supercapacitor. When using 1s supercapacitor, there is no need for cell balance, but still need MCU, SBC and motor driver.

Figure 4-9 1s Supercapacitor System Block: Buck Charge and Boost Discharge

• Bi-directional buck/boost converter to charge and discharge

Figure 4-10 shows the system block using the bi-directional buck/boost converter TPS61383-Q1 as charge and discharge chip. Compared with discrete design, the integrated design has lower costs, higher integration, and is also the trend in the future.

Figure 4-10 1s Supercapacitor System Block: Bi-directional Buck/Boost Converter