90E32 Datasheet, PDF (22/71 Pages) Integrated Device Technology – Poly-Phase High-Performance Wide-Span Energy Metering IC

90E32
POLY-PHASE HIGH-PERFORMANCE WIDE-SPAN ENERGY METERING IC
3.6.3 DETECTION MODE (D MODE)
In Detection mode, the current detector is active. The current detec-
tor compares whether any phase current exceeds the configured thresh-
old using low-power comparators.
When the current of one phase or multiple phases exceeds the con-
figured threshold, the 90E32 asserts the IRQ0 pin to high and hold it
until power mode change. The IRQ0 state is cleared when entering or
exiting Detection mode.
When the current of all three current channels exceed the configured
threshold, the 90E32 asserts the IRQ1 pin to high and hold it until power
mode change. The IRQ1 state is cleared when entering or exiting Detec-
tion mode.
The threshold registers need to be programmed in Normal mode
before entering Detection mode.
The digital I/O state is the same as that in Idle state (except for IRQ0/
IRQ1 and PM1/PM0).
The 90E32 has two comparators for detecting each phase’s positive
and negative current. Each comparator’s threshold can be set individu-
ally. The two comparators are both active by default, which called ‘dou-
ble-side detection’. User also can enable one comparator only to save
power consumption, which called ‘single-side detection’.
Double-side detection has faster response and can detect ‘half-wave’
current. But it consumes nearly twice as much power as single-side
detection.
Comparators can be power-down by configuring the DetectCtrl regis-
ter.
OSCI
OSCO
Power On Reset
Power Mode
Configuration
Current Detector
ADC-I1
ADC-I2
ADC-I3
ADC-V1
ADC-V2
ADC-V3
Temperature Sensor
Reference Voltage
VDD18 Regulator
Crystal Oscillator
Energy Metering
(Forward/Reverse
Active/Reactive/CF generator)
CF Out
DSP
Zero
Measure and Monitoring
(V/I/rms, SAG, Phase, Freq)
Crossing
Warn
Out
IRQ
Control Logic
SPI Interface
Figure-8 Block Diagram in Detection Mode
Function Description
22
December 9, 2011