Isolated, Digital Output, Power Monitoring IC
with Zero-Crossing Detection, Overcurrent and Overvoltage Flagging
ACS37800
Pulse Every Edge
The EEPROM field halfcycle_en is used to output a pulse at
every zero crossing.
Figure 16: halfcycle_en = 1, Both Rising and Falling
Zero Crossings Signaled
CONFIGURING THE DEVICE FOR AC APPLICATIONS
form a resistor divider network where,
Device EEPROM Settings
For AC power monitoring applications using the ACS37800, the
following device settings are recommended:
ꢅꢆꢄꢂꢆꢄ
ꢀ
ꢁꢂ
= ꢀ
∗
ꢃꢁꢂꢄ
ꢅꢁꢆꢇ1 + ꢅꢁꢆꢇ2 + ꢅꢆꢄꢂꢆꢄ
DYNAMIC CALCULATION OF N
RISO1 and RISO2 should be equal. A value of 1 MΩ is appropriate
for many applications, but ultimately, the resistance value used
needs to comply with the required isolation of the system.
Set bypass_n_en = 0 (default). This setting enables the device to
dynamically calculate N based off the voltage zero crossings. See
the Register Details – EEPROM section for additional details.
RISO1
RISO2
Voltage Measurement
VINP
1 MΩ
1 MΩ
RECOMMENDED APPLICATION CIRCUITS
An important aspect to consider when designing in the
RSENSE
ACS37800 into AC applications is the design of the voltage mea-
surement path. Typically, a resistor divider network is employed
to provide both isolation and transform the high voltage signal
into the ±250 mV signal that the ACS37800 can measure.
Vin
VINN
There are two basic application circuits recommended based on
the isolation requirements of the system. The first, see Figure 17,
is to be used when the ACS37800 GND and the neutral terminal
of the voltage input are connected. RISO1, RISO2, and RSENSE
Figure 17: Voltage Channel Application Circuit; Device
GND is Connected to Neutral
19
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955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
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