L6234 bootstrap capacitor 220 nF

[HBoch.1]

Should the 220nF bootstrap capacitor connected to ground or Vs? The circuit diagramm and the datasheet are describing it differently. Both can be found here: https://www.st.com/en/motor-drivers/l6234.html

Thank you.

[Cristiana SCARAMEL · Accepted solution]

Hello @Community member​ welcome to the ST Community.

First of all thank you for reporting this mismatch, we will update the Circuit diagram of web page with the datasheet figure.

Getting back to the topic: it is possible to use both setups, but we recommend the configuration with bootstrap capacitor connected between Vboot and Vs.

If the boot cap is connected to GND and Vs quickly drops, for example when a poorly load regulated supply sees a step change in current, the energy in Cboot would go into the chip and possibly damage it.

On the other hand if Cboot is connected to Vs and Vs drops, the entire charge pump circuitry drops so there would be no possibility of Cboot energy going into the chip.

Let me know if I addressed your concerns, if so please "Select as Best"