SEN012-013
SENZero
Family
Zero
1
Loss High Voltage Sense Signal Disconnect IC
Product Highlights
Features and Performance
•
Eliminates significant standby losses
•
Disconnects unnecessary circuit blocks during standby, remote-
•
•
High-Voltage
DC Rail
•
•
•
•
off, or light-load conditions
Ultra low leakage (maximum 1
mA)
650 V MOSFETs
•
<0.5 mW per channel during standby
Single component provides remote disconnect functionality
•
No external components or additional bias supply needed for
remote-off
•
Integrates multiple disconnect MOSFETs, gate drive, and
protection
•
Minimal component count provides higher reliability
Protection features to help production/manufacturing yields
•
Pin-to-pin fault and ESD protection
Triggerable via remote-off signal or load conditions
•
Integrated gate pull down circuit protects against loss of trigger
signal fault
Green package technology
•
RoHS compliant and halogen free
Withstands high differential surge conditions
•
S1, S2 and S3 interface with controller pins up to 6.5 V above
system ground
<3 mW loss at 230 VAC in Off/standby mode
System
V
CC
System
Standby
Signal
VCC
D1
D2
SENZero
System
Ground
Figure 1.
G
S1
S2
To Controller(s)
Sense Pins
PI-5813-032510
Typical Application SEN012.
High-Voltage
DC Rail
EcoSmart™–
Energy Efficient
•
Applications
System
V
CC
System
Standby
Signal
VCC
D1
D2
D3
•
ACDC converters with high-voltage resistive signal paths
•
Ideal for all very low standby systems such as those meeting EuP
Lot 6 and similar energy efficiency standards
Description
SENZero™ is a compact low-cost solution to eliminate losses in resistive
signal paths connected between high-voltage rails and switching power
supply controller(s). Examples include feed-forward or feedback signal
paths connected to boost controllers in power factor corrected systems
and feed-forward signal paths in two switch forward / LLC / half and
full bridge converters.
The device is available in 2 (SEN012) and 3 (SEN013) channel versions
according to the application’s requirements. The internal gate drive
and protection circuitry provides gate drive signals to the internal 650 V
MOSFETs in response to the voltage applied to the VCC pin. This
simple configuration provides easy integration into existing systems by
using the system V
CC
rail as an input to the SENZero.
The SENZero family uses a low cost compact SO-8 package to reduce
PCB area while the pin configuration is designed to meet pin-pin fault
conditions.
SENZero
System
Ground
Figure 2.
Typical Application SEN013.
G
S1
S2
S3
To Controller(s)
Sense Pins
PI-5812-032510
Component Selection Table
Product
2
Integrated Disconnect
MOSFETs
2
3
230 VAC
Power Consumption
in Standby
<1 mW
<1.5 mW
SEN012DG
SEN013DG
Table 1. Component Selection Table.
Notes:
1. IEC 16301 clause 4.5 rounds standby power use below 5 mW to zero.
2. Package: D: SO-8.
Figure 3.
SO-8 D Package.
www.power.com
May 2015
SEN012-013
SUPPLY (VCC)
DRAIN1 (D1)
DRAIN2 (D2)
DRAIN3 (D3)
Gate Drive
and
Protection
STEP
DOWN
SOURCE3 (S3)
SOURCE2 (S2)
GROUND (G)
SOURCE1 (S1)
PI-5815-012810
Figure 4.
SENZero Functional Block Diagram
SOURCE (S1, S2, S3) Pins:
Internally connect to the SOURCEs of MOSFETs 1, 2 and 3
respectively.
600
550
V
S
= 0
V
S
= 3
V
S
= 6.5
T
J
= 25 °C
R
DS(ON)
(Ω)
DRAIN (D1, D2, D3) Pins:
Internally connect to the DRAINs of MOSFETs 1, 2 and 3 respectively.
VOLTAGE SUPPLY (VCC) Pin:
The internal MOSFETs are fully turned on when the VCC pin voltage is
V
CC(ON)
(see parameter table) or more greater than their SOURCE
voltage relative to GROUND. VCC pin should be connected to
GROUND to turn the MOSFETs off.
GROUND (G) Pin:
This is the ground reference for all the SENZero pin voltages.
500
450
400
350
300
4
5
6
7
8
9
10
11
V
CC
-V
S
(V)
Figure 6.
Typical R
DS(ON)
as a Function of V
CC
-V
S
Voltage.
PI-5939-071610
D Package (SO-8)
SEN012DG
S1
D1
NC
S2
1
2
3
4
8
7
6
5
VCC
G
NC
D2
S1
D1
D2
S2
1
2
3
4
550
SEN013DG
8
7
6
5
VCC
G
D3
S3
V
CC
-V
S
= 6 V
V
CC
-V
S
= 5 V
500
R
DS(ON)
(Ω)
450
400
PI-5814-051710
Figure 5.
Pin Configuration.
350
0
1
2
3
4
5
6
7
V
S
(V)
Figure 7.
Typical R
DS(ON)
as a Function of V
S
Voltage.
2
Rev. C 05/15
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PI-5938-071610
Pin Functional Description
650
SEN012-013
Applications Considerations
The maximum voltage that the device can sustain across the
VOLTAGE SUPPLY and GROUND pin is 16 V. The maximum voltage
that any of the source channels can be at with respect to the ground
terminal is 6.5 V. SENZero has a typical on state resistance of
approximately 500
W
at room temperature. The device is therefore
typically used in series with high ohmic value resistors where this on
resistance is a small percentage of the total series impedance.
It is not necessary to provide a local bypass capacitor on the
VOLTAGE SUPPLY pin.
Operating Configurations for the SENZero
One configuration to power up the SENZero is shown in Figure 8. In
this circuit, SENZero is powered up from an unregulated bias winding
through a simple series pass regulator formed by Q1, R
B
and V
Z
. This
configuration ensures the VCC voltage is limited even if the maximum
bias voltage exceeds 16 V. During power-down, as soon as the bias
voltage falls below V
Z
, SENZero will turn off.
The series pass transistor Q1 is necessary only if the bias winding
voltage regulation is not tight enough (unregulated). If the voltage
on the bias winding is regulated or is such that the voltage on the
VOLTAGE SUPPLY pin can be maintained in the range 6 V < VCC < 16 V,
then the series pass transistor (Q1, R
B
and V
Z
) can be eliminated.
Unregulated
Bias
Q1
(2N3904)
VCC
D1
D2
A configuration that can be used to trigger remote-off functionality is
shown in Figure 9. In this configuration, a regulated auxiliary output
is used to power the IC. Transistor Q1 serves as the ON/OFF switch
which is commanded by the Enable/Disable signal at its base.
Regulated
Auxiliary
Q1
(2N3906)
VCC
D1
D2
R
A
(20 kΩ)
R
B
(2 kΩ)
SENZero
Disable
ON/OFF
G
S1
S2
PI-6051-072010
Figure 9.
SENZero Powered from a Regulated Auxiliary Winding.
An alternative remote-off configuration is shown in Figure 10 where
an unregulated bias voltage supplies the SENZero through a series
pass regulator similar to the one shown in Figure 8. However the
circuit of Figure 10 includes an ON/OFF transistor Q2. In other
versions of this circuit Q2 can be replaced by an optocoupler allowing
the ON/OFF disable signal to be communicated from a secondary of
the power supply such as in PC power supplies.
Unregulated
Bias
Q2
(2N3906)
Q1
(2N3904)
VCC
D1
D2
R
B
(2 kΩ)
V
Z
G
S1
S2
SENZero
R
B
(2 kΩ)
R
B
(100 kΩ)
ON/OFF
V
Z
G
S1
S2
SENZero
PI-6052-072010
Enable
PI-6053-110510
Figure 8.
SENZero Powered from an Unregulated Bias Winding Through a
Series Pass Regulator. Device is Enabled when Bias Voltage is
Present.
Figure 10. A Modified Version of an Unregulated Bias Winding Supplying Power
Through a Series Pass Regulator. Transistor Q2 Provides Remote-Off
Functionality.
3
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Rev. C 05/15
SEN012-013
Application Example
SENZero in PFC Bus Voltage Feedback Network
Commercial PFC IC’s typically has a pin dedicated for sensing the
output voltage of the PFC Stage. The information on this pin is
typically used by the PFC IC for various major functions.
VCC
1.
Output regulation – input to the non-inverting input of the error
2.
OVP detection – input to the OVP comparator.
3.
Open-loop protection – used to detect open-loop conditions.
The last 2 functions were used for protecting the bus from overvolt-
age condition.
amplifier.
SENZero
OFF
ON
OFF
ON
PFC
OFF
OFF
PI-6205-102510
PFC V
OUT
Figure 12. Timing between PFC IC and SENZero during Power-Up and
Power-Down.
C
BULK
R1
PFC IC
In case of shared VCC Connection, it must be ensure that SENZero
have a lower turn-on and turn-off threshold voltage compared to the
PFC IC.
PS
(ON)
ON
R2
OLP
SENZero
OFF
ON
OFF
R3
OVP
SENZero
Switch
FB
R
FB
PFC
OFF
ON
OFF
OFF
OFF
PI-6206-102510
Error Amplifier
Figure 13. Timing between PFC IC and SENZero with PS
(ON)
Signal.
PI-6203-102510
Figure 11. PFC Bus Voltage Sense Network.
From off-state to on-state, SENZero must turn-on ahead of the PFC.
From on-state to off-state, PFC must shutdown ahead of the
SENZero. This is to ensure that whenever PFC is operating (switch-
ing), SENZero is invincible to the PFC. SENZero only disconnects the
sense resistors when PFC is in off-condition and thus eliminates its
associated losses during standby condition.
The SENZero objective is to eliminate the losses associated with the
sense resistors without affecting the functionality of the circuit. To
keep the operation of the PFC IC unaffected, SENZero and PFC on
and off event must follow the required timing sequence during power-
up, power-down, remote-on, and remote-off event.
4
Rev. C 05/15
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SEN012-013
VCC
QA
UB
RA
2 kΩ
R1
10
Ω
D2
D1
VCC
OVP
C1
PFC IC
GND
C2
SENZero
GND
PI-6204-102510
Figure 14.
Typical Connection with PS
(ON)
Signal.
The figure above shows a typical VCC arrangement to satisfy timing
requirements.
Transistor QA is enabled during remote on condition. Capacitor C2
will charge through D1 while C1 is charged through R1. SENZero will
turn on ahead of PFC IC. Diode D2 makes C2 voltage tracks C1
voltage. Capacitor C2 can be increased to ensure that during
turn-off, PFC turns-off first before SENZero. Capacitors C1 and C2
can be 100 nF standard decoupling capacitors. However, C1 needs to
be ≥C2.
5
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Rev. C 05/15
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