STPM32 datasheet(38/89 Pages) STMICROELECTRONICS

38 / 89 page

Figure 43. Sag detection process

VFUND

+ SAG_THRx

SAG_TIME

SAG_EV = 0000

0001

0010

0101

1011

SAG_TIME_THR

- SAG_THRx

SAG_TIME_THR

SAG Event

Start

SAG Event

End

SAG Event

Start

Overflow

Reset state

Voltage/current swell detection

To detect a voltage or a current swell, the fundamental component of signal is compared to the 10-bit threshold

SWV_THRx[9:0] and SWC_THRx[9:0] in DSP_CR5, DSP_CR6, DSP_CR7 and DSP_CR8.

When the signal overcomes the threshold, a swell event is detected and LSB of SWVx_EV[3:0] or SWCx_EV[3:0]

event register is set. At the same time, SWELL_Start bit is set in the interrupt status register and an interrupt can

be generated.

If the swell event ceases, SWV_EV or SWC_EV register is shifted and its LSB is set to zero, also SWELL_End bit

in the interrupt status register is set.

The duration of the event is stored in SWV_TIME[14:0] or SWC_TIME[14:0] in registers from DSP_REG16 to

DSP_REG19 for primary and secondary voltage and current channel respectively.

If the overflow of SWV_TIME or SWC_TIME register occurs, the related SWVx_EV and SWCx_EV register is left

shifted and its LSB is set, as shown in figure below.

LSB of time registers is 8 μs.

To disable swell detection, the registers SWV_THRx and SWC_THRx must have maximum value 0x3FF.

STPM32, STPM33, STPM34

Functional description of hardwired DSP

DS10272 - Rev 13

page 38/89

STPM32 Datasheet(PDF) 38 Page - STMicroelectronics