Comparator (COMP) RM0453
626/1454 RM0453 Rev 2
21.3.7 Comparator output blanking function
The purpose of the blanking function is to prevent the current regulation to trip upon short
current spikes at the beginning of the PWM period (typically the recovery current in power
switches anti parallel diodes). It uses a blanking window defined with a timer output
compare signal. Refer to the register description for selectable blanking signals. The
blanking signal gates the internal comparator output such as to clean the comp_out from
spurious pulses due to current spikes, as depicted in the figure below.
Figure 97. Comparator output blanking
21.3.8 COMP power and speed modes
COMP1 and COMP2 power consumption versus propagation delay can be adjusted to have
the optimum trade-off for a given application.
PWRMODE[1:0] bits in COMPx_CSR registers can be programmed as follows:
00: High speed/full power
01: Medium speed/medium power
10: Medium speed/medium power
11: Very-low speed/ultra-low-power
MS30964V2
Inverting input
(represents current limit)
Non-inverting input
(represents current)
cmp_out
(before blanking gate)
cmp_blk
(blanking window)
comp_out
(COMP output)
PWM
cmp_out
cmp_blk
comp_out (to I/Os, TIM_BK …)
Blanking gate
current
spike
spurious
pulse
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