st7pmc2s6 STMicroelectronics, st7pmc2s6 Datasheet - Page 237

• Manufacturer Part Number: st7pmc2s6
• Description: 8-bit Mcu For Automotive With Nested Interrupts, Flash, 10-bit Adc, Brushless Motor Control, 5 Timers, Spi, Linsci?
• Manufacturer: STMicroelectronics

ST7MC1K2-Auto, ST7MC1K6-Auto, ST7MC2S4-Auto, ST7MC2S6-Auto
Note:
Note:
Current feedback amplifier
In both current and voltage mode, the current feedback from the motor can be amplified
before entering the comparator. This is done by an integrated op-amp that can be used
when the OAON bit is set in the OACSR register and the CFAV bit in the MREF register is
reset. This allows the three points of the op-amp to be accessed for a programmable gain.
The CFAV bit in the MREF register selects the MCCFI0 or OAZ(MCCFI1) pin as the
comparator input as shown in the following table.
Table 104. Comparator input selection
If the amplifier is not used for current feedback, it can be used for other purposes. In this
case, the OAON bit in the OACSR register and the CFAV bit in the MREF register both have
to be set. This means that the current feedback has to be on the MCCFI0 pin to be directly
connected to the comparator and the OAP, OAN and OAZ (MCCFI1) pins can be used to
amplify another signal. Both the OAZ(MCCFI1) and MCCFI0 pins can be connected to an
ADC entry. See
The MCCFI0 pin is not available in LQFP32 and LQFP44 devices. In this case, the CFAV bit
must be reset. The choice to use the op-amp or not is made with the OAON bit.
Measurement window
In current mode, the measurement window frequency can be programmed between 390Hz
and 50 kHz by the means of the SA[3:0] bits in the MPRSR register.
These frequencies are given for a 4 MHz peripheral input frequency for a BLDC drive (XT16,
XT8 bits in MCONF register).
In sensorless mode this measurement window can be used to detect BEMF zero crossing
events. Its width can be defined between 2.5 s and 40 s as a minimum in sensorless mode
by the OT[3:0] bits in the MPWME register.
This sets the minimum off time of the PWM signal generated by this internal clock. This off
time can vary depending on the output of the current feedback comparator. In sensor mode
(SR = 1) and when the sampling for the Z event is done during the PWM ON time in
sensorless mode (SPLG bit is set in MCRC register and/or DS[3:0] bits with a value other
than 000 in MCONF register), there is no minimum OFF time required anymore, the
minimum off time is set automatically to 0µs and the OFF time of the PWM signal is
controlled only by the current regulation loop.
CFAV bit
0
1
(Figure
107).
Select OAZ(MCCFI1) as the current comparator input
Select MCCFI0 as the current comparator input
Meaning
On-chip peripherals
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