NCS37020
SUP
AUX
12V Shunt
Regulator
3.3V Analog
Regulator
3.3V Digital
Regulator
1.65V
CTB
IDF
−
+
REF
Bandgap
Reference
1.2V
3.3V Analog Regulator
Voltage Divider
2MHz
Oscillator
POR
NCS37020
+0.25V
+
SCR
− + /
−0.25V
−
data[7:0]
SAR
Digital
Filter
Fault Test
ADC
done
Saturation
Clamp/
adc_start
clk
Detection
TE
CTO
+
−
CONTROL LOGIC
GROUND FAULT
LED
DYNAMIC OSC TRIM
SCR Test
GND
CTS
Phase
chop
saturated
OFFSET CORRECTION
3.3V Shunt
Regulator
Figure 1. Simplified Block Diagram
Pad Description
Table 1. TSSOP PIN DESCRIPTION
Pin #
1
Name
SCR Test
CTB
SCR test input for SCR functionality
2
Differential current transformer bias voltage
Differential current signal input
Differential current to voltage output
Differential low pass filter/ADC input
3.3 V Internal reference voltage
Electronics ground
3
CTS
4
CTO
5
IDF
6
REF
7
GND
Phase
SUP
8
Zero cross input for V frequency
AC
9
Power supply input
10
11
12
13
14
AUX
Auxiliary power supply input
End of life LED drive
LED
TE
Test enable, Connect to GND
Differential self−test output signal
SCR gate drive signal
Fault Test
SCR
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