Bootstrap capacitor (Cbs) Precharging

pratibhasurabhi — Thu, 21 May 2020 11:22:09 GMT

Hi all,

I am referring MC9S12ZVM-Family RM.(Rev 2.13)

In the chapter 1.13.8.2.1 Bootstrap Precharge

The below chunk of data :

***********************************************************Start**********************************************************

The bootstrap capacitors must be precharged before turning on the high-side drivers for the first time. This
can be done by using the PMF software output control mechanism:
PMFOUTC = 0x3F; // SW control on all outputs
PMFOUTB = 0x2A; // All high-sides off, all low-sides on
The PWM0 signals should be configured to start with turning on the low-side before the high-side drivers
in order to assure precharged bootstraps. Therefore invert the PWM0 signals:
PMFCINV = 0x3F; // Invert all channels to precharge

*********************************************************End*************************************************************

Query is whether the above advisory of pre-charging bootstrap and inverting PWM0 signals is applicable for all versions of GDU i.e. GDUV4, GDUV5, GDUV6 or for a specific version

Thanking in advance

Re: Bootstrap capacitor (Cbs) Precharging

danielmartynek — Mon, 25 May 2020 07:35:19 GMT

Hi Pratinha,

Yes, it applies to all the GDU versions.

Because the capacitor is charged only when the corresponding LS driver is active.

Regards,

Daniel

topic Re: Bootstrap capacitor (Cbs) Precharging in S12 / MagniV Microcontrollers

Bootstrap capacitor (Cbs) Precharging

Re: Bootstrap capacitor (Cbs) Precharging