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-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
EcoSmart
®
– Energy Efficient
•
<3 mW loss at 230 VAC in Off/standby mode
Applications
•
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
High-Voltage
DC Rail
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
System
V
CC
System
Standby
Signal
VCC
D1
D2
D3
Description
SENZero
System
Ground
Figure 2.
G
S1
S2
S3
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 feedforward 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.
To Controller(s)
Sense Pins
PI-5812-032510
Typical Application SEN013.
Component Selection Table
Product
2
SEN012DG
SEN013DG
Integrated Disconnect
MOSFETs
2
3
230 VAC
Power Consumption
in Standby
<1 mW
<1.5 mW
Table 1. Component Selection Table.
Notes:
1. IEC
62301
clause 4.5 rounds standby power use below 5 mW to zero.
2. Package: D: SO-8.
www.powerint.com
November 2010
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 3.
SENZero Functional Block Diagram
SOURCE (S1, S2, S3) Pins :
Internally connect to the SOURCEs of MOSFETs 1, 2 and 3
respectively.
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.
R
DS(ON)
(Ω)
600
550
500
450
400
350
300
4
5
6
7
8
9
V
S
= 0
V
S
= 3
V
S
= 6.5
T
J
= 25 °C
10
11
V
CC
-V
S
(V)
Figure 5.
Typical R
DS(ON)
as a Function of V
CC
-V
S
Voltage.
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
V
CC
-V
S
= 6 V
V
CC
-V
S
= 5 V
SEN013DG
8
7
6
5
VCC
G
D3
S3
500
R
DS(ON)
(Ω)
450
400
PI-5814-051710
350
Figure 4.
Pin Configuration.
0
1
2
3
4
5
6
7
V
S
(V)
Figure 6.
Typical R
DS(ON)
as a Function of V
S
Voltage.
2
Rev. B 11/05/10
www.powerint.com
PI-5939-071610
550
PI-5938-071610
Pin Functional Description
650
SEN012-013
Applications Considerations
The maximum voltage that the device can sustain across the
VCC and G 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 approxi-
mately 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
VCC pin.
Operating Configurations for the SENZero
One configuration to power up the SENZero is shown in Figure 7.
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 VCC 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 8. 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 8.
SENZero Powered From a Regulated Auxiliary Winding.
An alternative remote-off configuration is shown in Figure 9
where an unregulated bias voltage supplies the SENZero
through a series pass regulator similar to the one shown in
Figure 7. However the circuit of Figure 9 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)
R
B
(2 kΩ)
Q1
(2N3904)
VCC
D1
D2
R
B
(2 kΩ)
V
Z
G
S1
S2
SENZero
V
Z
G
S1
S2
PI-6053-110510
SENZero
ON/OFF
R
B
(100 kΩ)
Enable
PI-6052-072010
Figure 9.
Figure 7.
SENZero Powered from an Unregulated Bias Winding Through a Series
Pass Regulator. Device is Enabled When Bias Voltage is Present.
A Modified Version of an Unregulated Bias Winding Supplying Power
Through a Series Pass Regulator. Transistor Q2 Provides Remote-Off
Functionality.
3
www.powerint.com
Rev. B 11/05/10
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.
1. Output regulation – input to the non-inverting input of the
error amplifier
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
overvoltage condition.
VCC
SENZero
OFF
ON
OFF
ON
PFC
OFF
OFF
PI-6205-102510
Figure 11. Timing between PFC IC and SENZzero during Power-up and
Power-Down.
PFC V
OUT
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.
C
BULK
R1
PFC IC
PS
(ON)
OFF
ON
OFF
ON
R2
OLP
SENZero
OFF
OFF
ON
R3
OVP
SENZero
Switch
FB
R
FB
PFC
OFF
OFF
PI-6206-102510
Figure 12. Timing between PFC IC and SENZero with PS
(ON)
Signal.
Error Amplifier
PI-6203-102510
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
(switching), 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.
Figure 10.
PFC Bus Voltage Sense Network.
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. B 11/05/10
www.powerint.com
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 13.
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
www.powerint.com
Rev. B 11/05/10
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
