Fairchild FAN4146SX Ground fault interrupter Datasheet

FAN4146 — Ground Fault Interrupter
Features
Description
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The FAN4146 is a low-power controller for AC outlet
Appliance Leakage Circuit Interrupters (ALCI) and twowire Residual Current Devices (RCD). The FAN4146
detects hazardous grounding conditions and open
circuits the line before a harmful shock occurs.
For Two-Wire ALCI and RCD Applications
Precision Sense Amplifier and Bandgap Reference
Built-in AC Rectifier
Direct DC Coupled to Sense Coil
Internally, the FAN4146 contains a diode rectifier,
precision bandgap 12V shunt regulator, precision low
VOS offset-sense amplifier, time delay noise filter,
window-detection comparators, and a SCR driver. With
the addition of a minimum number of external
components, the FAN4146 detects and protects against
a hot-wire-to-ground fault. The minimum number of
components and the small SuperSOT™ package allow
for a small-form-factor, low-cost application solution.
Built-in Noise Filter
Low-Voltage SCR Disable
SCR Gate Driver
Adjustable Sensitivity
Minimum External Components
Meets UL 943B Requirements
Ideal for 120V or 220V Systems
Space-Saving SuperSOT™ 6-Pin Package
Applications
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Personal Care Products
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ALCI and RCCB Circuits
Two-Wire Electrical Outlets, Circuit Breakers, and
Power Cords Requiring GFI Safety Features
The FAN4146 circuitry has a built-in rectifier and shunt
regulator that operates with a low quiescent current.
This allows for a high-value, low-wattage-series supply
resistor. The internal temperature compensated shunt
regulator, sense amplifier, and bias circuitry provide for
precision ground-fault detection. The low VOS offsetsense amplifier allows direct coupling of the sense coil
to the amplifier’s feedback signal. This eliminates the
large 50/60Hz AC-coupling capacitor. The internal delay
filter rejects high-frequency noise spikes common with
inductive loads. This decreases false nuisance tripping.
The internal SCR driver is temperature compensated
and designed to satisfy the current requirements for a
wide selection of external SCRs.
The minimum number of external components and the
6-pin SuperSOT™ package enable for a low-cost,
compact design and layout. The FAN4146ESX is an
enhanced temperature range device.
Ordering Information
Part Number
Operating
Temperature Range
Package
Packing Method
FAN4146SX
0°C to +70°C
6-Lead SUPERSOT6, JEDEC MO-193, 1.6mm
Tape and Reel
FAN4146ESX
-25°C to +80°C
6-Lead SUPERSOT6, JEDEC MO-193, 1.6mm
Tape and Reel
© 2010 Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
FAN4146 — Ground Fault Interrupter
August 2010
FAN4146 — Ground Fault Interrupter
Typical Applications
Figure 1.
120/220VAC ALCI Application
(2)
Typical Values
R1: 91KΩ (Wattage Determined by Maximum VAC)
RTEST: 15KΩ
(1)
RSET: 511KΩ
RIN: 470Ω
C1: 22nF
Note:
1. Value depends on sense-coil characteristics and application (value chosen for 5mA trip threshold).
2. Contact Fairchild for best application practices for nuisance tripping rejection.
Figure 2.
220VAC RCD Application
(4)
Typical Values
R1: 174KΩ (Wattage Determined by Maximum VAC)
RSET: 324KΩ
RTEST: 15KΩ
RIN: 470Ω
(3)
C1: 22nF
C2: 10nF
Note:
3. Value depends on sense-coil characteristics and application (value chosen for 10mA trip threshold).
4. Contact Fairchild for best application practices for nuisance tripping rejection.
© 2010 Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
2
FAN4146 — Ground Fault Interrupter
Block Diagram
Figure 3.
Block Diagram
Pin Configuration
Figure 4.
Pin Configuration
Pin Definitions
Pin #
Name
Description
1
SCR
2
Neutral
Supply input for FAN4146 circuitry
3
Line
Supply input for FAN4146 circuitry
4
VREF
5
VFB
6
AmpOut
Gate drive for external SCR
Non-inverting input for current-sense amplifier
Inverting input for current-sense amplifier
External resistor connected to VFB sets the Ifault sensitivity threshold
© 2010 Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
3
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device
reliability. The absolute maximum ratings are stress ratings only.
Symbol
Parameter
Condition
Min.
ICC
Supply Current
Continuous Current, Line to Neutral
VCC
Supply Voltage
TSTG
Storage Temperature Range
ESD
Electrostatic Discharge Capability Charged Device Model, JESD22-C101
All other pins
Max.
Unit
15
mA
Continuous Voltage, Line to Neutral
-1.5
16.0
V
Continuous Voltage to Neutral
-0.8
15.0
V
-65
+150
°C
Human Body Model, JESD22-A114
2500
1000
Machine Model, JESD22-A115
V
200
FAN4146 — Ground Fault Interrupter
Absolute Maximum Ratings
DC Electrical Characteristics
Unless otherwise specified, TA=25°C, Ishunt=1mA.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
13.2
Units
Power Supply Shunt Regulator
Voltage
Line to Neutral
12.2
12.7
Line to Neutral, Ishunt=-2mA
-0.9
-0.7
IQ
Quiescent Current
Line to Neutral=10V
350
400
450
µA
VREF
Reference Voltage
VREF to Neutral
5.8
6.0
6.2
V
VTH
Trip Threshold
AmpOut to VREF
3.4
3.5
3.6
V
VOS
Amplifier Offset
RSET=511KΩ, RIN=500Ω
-450
0
450
µV
Design Value
-50
0
50
nA
VREG
IOS
G
Amplifier Input Offset
Amplifier DC Gain
(5)
(5)
(5)
Design Value
100
dB
Design Value
1.5
MHz
fGBW
Amplifier Gain Bandwidth
VSW+
Amplifier Positive Voltage Swing
VSW-
Amplifier Negative Voltage Swing VREF to AmpOut, IFAULT=-10µA
AmpOut to VREF, IFAULT=10µA
4.0
V
4.0
V
400
µA
µA
ISINK
Amplifier Current Sink
AmpOut=VREF + 3V,
VFB=VREF + 100mV
ISRL
Amplifier Current Source
AmpOut=VREF – 3V,
VFB=VREF - 100mV
400
Delay Filter
Delay from C1 Trip to SCR,
LOW to HIGH
0.75
ROUT
SCR Output Resistance
SCR to Neutral=250mV,
AmpOut=VREF
VOUT
SCR Output Voltage
IOUT
SCR Output Current
td
V
SCR to Neutral, AmpOut=VREF
SCR to Neutral,
AmpOut =VREF +4V
2.5
SCR to Neutral=1V
AmpOut=VREF + 4V
350
1.00
1.25
ms
0.5
1.0
KΩ
1
10
mV
V
500
µA
Note:
5. Guaranteed by design; not tested in production.
© 2010 Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
4
Refer to Figure 1 and Figure 3.
Calculation of RSET Resistor
The FAN4146 is a two-wire GFCI controller for AC
ground-fault-circuit interrupters. The internal rectifier
circuit is biased by the AC line during the positive half
cycle of the AC line voltage. The internal 12V shunt
regulator uses a precision temperature-compensated
bandgap reference. The combination of precision
reference circuitry and precision sense amplifier
provides for an accurate ground-fault tolerance. This
allows for selection of external components with wider
and lower-cost parameter variation. Due to the low
quiescent current, a high value external series resistor
(R1) can be used which reduces the maximum power
wattage required for this resistor. The 12V shunt
regulator generates the reference voltage VREF for the
sense amplifier’s (A1) non-inverting input (AC ground
reference) and supplies the bias for the delay timer (t1),
comparators (C1 & C2), and the SCR driver.
The AmpOut signal must exceed the window
comparator’s VTH threshold voltage for longer than the
delay timer and calculated by:
(1)
RSET = (VTH x N) / (1.41 x IFAULT x COS(π x t/P))
(2)
where:
VTH
= 3.5V
IFAULT = 5mA (UL943B)
t
= 1ms (timer delay)
P
= Period of the AC Line (1/60Hz)
N
= Ratio of secondary to primary turns (1000:1)
RSET = 505KΩ (511KΩ standard 1% value)
The secondary winding of the sense transformer is
directly DC coupled to the inverting input of the sense
amplifier at pin 5 (VFB). The RSET resistor converts the
sense transformer’s secondary current to a voltage at
pin 6 (AmpOut). This voltage is compared to the internal
window comparator (C1 & C2) and, when the AmpOut
voltage exceeds the +/-VTH threshold voltage, the
window comparator triggers the internal delay timer.
The output of the window comparator must stay HIGH
for the duration of the t1 timer. If the window
comparator’s output momentarily goes LOW, the t1
timer resets. If the window comparator’s output is still
HIGH at the end of the t1 pulse, the SCR driver enables
the current source I1 and disables Q1. The current
source I1 then enables the external SCR, which
energizes the solenoid, opens the contact switches to
the load, and removes the hazardous ground fault. The
window comparator allows detection of a positive or
negative IFAULT signal independent from the phase of
the line voltage. An internal under-voltage lockout circuit
disables the SCR driver if the voltage at pin 3 (LINE) is
below 7.5V. This prevents the SCR from energizing the
solenoid when the SCR’s anode voltage is below 65V.
In practice, the transformer is non-ideal, so RSET may
need to be adjusted by up to 30% to obtain the desired
Ifault trip threshold.
Calculation of VOS Trip Threshold Error
Since the sense coil is directly connected to the
feedback of the sense amplifier, the VOS offset
introduces an Ifault threshold error. This error can be
calculated as follows:
%Error=100 x (VOS x RSET) / (RIN + RLDC + RLAC) / VTH
(3)
where:
+/-450µV (worst case)
+/-150µV (typical)
VOS
=
RSET
= 511KΩ
RIN
= 470Ω (typical value)
RLDC = 75Ω (sense coil secondary DC resistance)
The sense transformer typically has a toroidal core
made of laminated steel rings or solid ferrite material.
The secondary of the transformer is typically 1000 turns
of #40 wire wound through the toroid. The primary is
typically one turn made by passing the AC hot and
neutral wires through the center of the toroid. When a
ground fault exists, a difference exists between the
current flowing in hot and neutral wires. The primary
difference current divided by the primary-to-secondary
turns ratio is the current that flows through the
secondary wire of the transformer.
© 2010 Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
VTH=IFAULT x 1.41 x RSET x COS(2π x (t/2P)) / N
FAN4146 — Ground Fault Interrupter
Functional Description
RLAC =
VTH
1.5 KΩ (AC(jωL) impedance of sense coil),
L= 4H, f= 60Hz)
= 3.5V
%Error=
+/- 3.2% (worst case)
+/- 1.1% (typical)
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FAN4146 — Ground Fault Interrupter
Typical Performance Characteristics
Unless otherwise specified, TA=25°C and according to Figure 1 with SCR disconnected.
Ch1: VLine (Pin 3), 10V/Div
Ch1: VLine (Pin 3), 10V/Div
Ch2: AmpOut (Pin 6), 10V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch3: VREF (Pin 4), 10V/Div
Ch3: SCR (Pin 1), 1V/Div
Ch4: VAC Input, 200V/Div
Ch4: IFAULT, 10mA/Div
Figure 5.
Typical Waveforms, No Ground Fault
Figure 6.
Typical Waveforms, 4mA Ground Fault
Ch1: VLine (Pin 3), 10V/Div
Ch1: VLine (Pin 3), 10V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch3: SCR (Pin 1), 1V/Div
Ch3: SCR (Pin 1), 1V/Div
Ch4: IFAULT, 10mA/Div
Ch4: IFAULT, 10mA/Div
Figure 7.
Figure 8.
Typical Waveforms, 5mA Ground Fault
Typical Waveforms, 5mA Ground Fault
(Line Polarity Reversal)
Continued on the following page…
© 2010Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
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FAN4146 — Ground Fault Interrupter
Typical Performance Characteristics (Continued)
Unless otherwise specified, TA=25°C and according to Figure 1 with SCR disconnected.
1ms
1ms after AmpOut signal reaches 9.5V, SCR is triggered.
Ch1: VLine (Pin 3), 10V/Div
Ch1: VLine (Pin 3), 10V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch3: SCR (Pin 1), 1V/Div
Ch3: SCR (Pin 1), 2V/Div
Ch4: IFAULT, 10mA/Div
Ch4: IFAULT, 10mA/Div
Figure 9.
AmpOut Threshold, Internal 1ms Delay
Figure 10.
15KΩ Ground Fault
Ch1: VLine (Pin 3), 10V/Div
Ch2: AmpOut (Pin 6), 5V/Div
Ch3: SCR (Pin 1), 2V/Div
Ch4: IFAULT, 500mA/Div
Figure 11.
(6, 7)
500Ω Ground Fault
Note:
6. Maximum trip time ~12ms.
7. Fault occurs at the end of the positive AC cycle.
© 2010Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
7
% Difference from 25°C
2
1.5
1
0.5
0
‐0.5
‐1
‐1.5
‐2
‐25
‐5
15
35
55
75
Temperature °C
Figure 12.
FAN4146 — Ground Fault Interrupter
Typical Temperature Characteristics (FAN4146E)
VThreshold (VTH) vs. Temperature
% Difference from 25°C
1
0.5
0
‐0.5
‐1
‐25
‐5
15
35
55
75
Temperature °C
Figure 13.
VReference (VREF) vs. Temperature
% Difference from 25°C
5
2.5
0
‐25
‐5
15
35
55
75
‐2.5
‐5
Temperature °C
Figure 14.
© 2010Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
SCR Output Current (IOUT) vs. Temperature
www.fairchildsemi.com
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FAN4146 — Ground Fault Interrupter
Physical Dimensions
Figure 15.
6-Lead SUPERSOT6, JEDEC MO-193, 1.6mm Wide
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify
or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically
the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2010Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
9
FAN4146 — Ground Fault Interrupter
© 2010Fairchild Semiconductor Corporation
FAN4146 • Rev. 1.0.0
www.fairchildsemi.com
10