STPM32 datasheet(57/121 Pages) STMICROELECTRONICS

No. de pieza	STPM32

Descripción Electrónicos	ASSP for metering applications with up to four independent 24-bit 2nd order sigma-delta ADCs, 4 MHz OSF and 2 embedded PGLNA

PDF	121 Pages

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Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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57 / 121 page

DS10272 Rev 8

57/121

STPM32, STPM33, STPM34

Theory of operation

121

Figure 43. Sag detection process

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

s.

To disable swell detection, the registers SWV_THRx and SWC_THRx must have maximum

value 0x3FF.

STPM32 Datasheet(PDF) 57 Page - STMicroelectronics