Data Sheet

TEA1792T
GreenChip synchronous rectifier controller
Rev. 2 — 9 July 2012
Product data sheet
1. General description
The TEA1792T is a member of the new generation of Synchronous Rectifier (SR)
controller ICs for switched mode power supplies. Its high level of integration allows the
design of a cost-effective power supply with a very low number of external components.
The TEA1792T is a controller IC dedicated to synchronous rectification on the secondary
side of discontinuous conduction mode and quasi-resonant flyback converters.
The TEA1792T is fabricated in a Silicon-On-Insulator (SOI) process.
2. Features and benefits
2.1 Distinctive features





Accurate synchronous rectification functionality
Wide supply voltage range (8.5 V to 38 V)
High level of integration, resulting in a very low external component count
High driver output voltage of 10 V to drive all MOSFET brands to the lowest RDSon
Selectable regulation level for driver stage
2.2 Green features
 Low current consumption
 High system efficiency from no load to full load
2.3 Protection features
 UnderVoltage Protection (UVP)
3. Applications
 The TEA1792T is intended for adapters. The device can also be used in all other
discontinuous conduction mode systems and quasi-resonant flyback systems that
demand a highly efficient and cost-effective solution.
TEA1792T
NXP Semiconductors
GreenChip synchronous rectifier controller
4. Ordering information
Table 1.
Ordering information
Type number
Package
TEA1792T/N1
Name
Description
Version
SO8
plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
5. Block diagram
9&&
—$
6(/5(*
'(7(&7,21
6833/<
$1'%,$6
89/2
FRQWURO
656(16(
5
4
6
4
7,0(5
'5,9(5
P9
P9
P9
P9
GULYHU
7($
*1'
See Table 2 for details on the pinning.
(1) 1.8 s and 2.1 s.
Fig 1.
Block diagram
TEA1792T
Product data sheet
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6. Pinning information
6.1 Pinning
SRSENSE
1
GND
2
8
VCC
7
n.c.
TEA1792T
n.c.
3
6
SELREG
DRIVER
4
5
n.c.
aaa-000136
Fig 2.
Pin configuration
6.2 Pin description
Table 2.
TEA1792T
Product data sheet
Pin description
Symbol
Pin
Description
SRSENSE
1
synchronous timing input
GND
2
ground
n.c.
3
not connected
DRIVER
4
driver output for SR MOSFET
n.c
5
not connected
SELREG
6
selection input for driver regulation level
n.c.
7
not connected
VCC
8
supply voltage
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7. Functional description
7.1 Introduction
The TEA1792T is the controller for synchronous rectification used in discontinuous
conduction mode and quasi-resonant flyback converters.
7.2 Start-up and UnderVoltage LockOut (UVLO)
The IC leaves the undervoltage lockout state and activates the synchronous rectifier
circuitry when the voltage on the VCC pin is above 8.5 V (typical). When the voltage drops
below 8.0 V (typical), the undervoltage lockout state is entered again and the SR driver
output is actively kept low.
7.3 Synchronous rectification
After a negative voltage lower than Vact(drv) (220 mV typical) is sensed on the SRSENSE
pin, the driver output voltage is driven HIGH. Then the external MOSFET is switched on.
When the SRSENSE voltage rises to Vreg(drv) 42 mV/30 mV), the driver output voltage
is regulated to maintain the Vreg(drv) on the SRSENSE pin. When the SRSENSE voltage is
above the Vdeact(drv) level (12 mV typical), the driver output is pulled to ground.
After switch-on of the SR MOSFET, the input signal on the SRSENSE pin is blanked
during the tact(sr)(min) (1.8 s typical). This action eliminates false switch-off due to high
frequency ringing at the start of the secondary stroke.
When the voltage on the SRSENSE pin is Vreg(drv), the driver output voltage is reduced.
This reduction enables the external power switch to be switched off quickly when the
current through the switch reaches zero. The zero current switch-off removes the need for
a separate Standby mode to maintain high efficiency during the no-load operation. The
zero current is detected by sensing a Vdeact(drv) (12 mV typical) level on the SRSENSE
pin (see Figure 3).
TEA1792T
Product data sheet
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GreenChip synchronous rectifier controller
VSRSENSE
0V
Vdeact(drv) (-12 mV typ.)
Vreg(drv) (-42 mV/-30 mV typ.)
Vact(drv) (-220 mV typ.)
primary
current
0A
secondary
current
0A
VDRIVER
0V
aaa-000137
Fig 3.
Synchronous rectification signals
The level of the driver regulation voltage Vreg(drv) can be selected using the SELREG pin.
When this SELREG pin is grounded, the typical Vreg(drv) equals 42 mV. When the
SELREG pin is left open, the Vreg(drv) level equals 30 mV.
Internally, the SELREG pin has a pull-up current source of 10 µA. When this pin is short
circuited to ground, the pin selects the lowest Vreg(drv). If the pin is left open, the highest
Vreg(drv) value is selected.
If the secondary stroke of the flyback converter is shorter than tact(sr)(min) short time (1.8 s
typical), the driver output is disabled. This action guarantees stable operation for very low
duty cycles. When the secondary stroke increases above tact(sr)(min), long time (2.1 s
typical), the driver output is again enabled.
7.4 Supply management
All internal reference voltages are derived from a temperature compensated, on-chip
band gap circuit.
7.5 Driver
The driver circuit to the external power MOSFET gate has a typical source capability of
400 mA and a typical sink capability of 2.7 A. These capabilities permit fast switch-on and
switch-off of the power MOSFET for efficient operation. The source stage is coupled to the
timer (see Figure 1). When the timer has finished, the source capability is reduced to a
small current (5 mA typical) capable of keeping the driver output voltage at its level.
TEA1792T
Product data sheet
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GreenChip synchronous rectifier controller
The output voltage of the driver is limited to 10 V (typical). This high output voltage drives
all MOSFET brands to the minimum on-state resistance.
During start-up conditions (VCC < Vstartup) and undervoltage lockout the driver output
voltage is actively pulled low.
8. Limiting values
Table 3.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134). All voltages are measured
with respect to ground (pin 2); positive currents flow into the chip. The voltage ratings and current
ratings are valid provided the other ratings are not violated.
Symbol
Parameter
Conditions
Min
Max
Unit
VCC
supply voltage
continuous
0.4
+38
V
VSRSENSE
voltage on pin SRSENSE continuous
-
120
V
VSELREG
voltage on pin SELREG
continuous
0.4
+5
V
IDRIVER
current on pin DRIVER
duty cycle < 10 %
0.8
+3
A
ISRSENSE
current on pin SRSENSE
3
-
mA
-
0.45
W
Voltages
Currents
General
Tamb < 80 C
Ptot
total power dissipation
Tstg
storage temperature
55
+150
C
Tj
junction temperature
40
+150
C
2
+2
kV
500
+500
V
VESD
electrostatic discharge
voltage
human body model; JEDEC
Class 2; all pins
[1]
charged device model;
JEDEC Class 3; all pins
[1]
Equivalent to discharging a 100 pF capacitor through a 1.5 k series resistor.
9. Thermal characteristics
Table 4.
TEA1792T
Product data sheet
Thermal characteristics
Symbol
Parameter
Conditions
Typ
Unit
Rth(j-a)
thermal resistance from junction
to ambient
JEDEC test board
157
K/W
Rth(j-c)
thermal resistance from junction
to case
JEDEC test board
90
K/W
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GreenChip synchronous rectifier controller
10. Characteristics
Table 5.
Characteristics
Tamb = 25 C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
8.2
8.5
8.8
V
0.35
0.5
0.65
V
VCC = 8 V (VCC < Vstartup)
0.2
0.25
0.4
mA
under normal operation; no load on
pin DRIVER
0.8
1
1.2
mA
260
220
180
mV
resistance between pins SELREG
and GND < 15 k
55
42
30
mV
resistance between pins SELREG
and GND > 700 k
38
30
22
mV
Supply voltage management (pin VCC)
Vstartup
start-up voltage
Vhys
hysteresis voltage
ICC(oper)
operating supply current
[1]
Synchronous rectification sense input (pin SRSENSE)
Vact(drv)
driver activation voltage
Vreg(drv)
driver regulation voltage
Vdeact(drv)
driver deactivation voltage
-
12
-
mV
td(act)(drv)
driver activation delay
time
50
75
100
ns
tact(sr)(min)
minimum synchronous
rectification active time
short time
1.3
1.8
2.3
s
long time
1.6
2.1
2.6
s
Io(SELREG)
output current on pin
SELREG
VSELREG = 2.5 V
12
10
8
A
during minimum synchronous
rectification time
0.45
0.4
0.35
A
minimum synchronous
rectification time has ended
6
5
4
mA
1
1.4
-
A
2.2
2.7
-
A
9
10
12
V
Driver (pin DRIVER)
Isource
source current
VCC = 15 V; voltage on
pin DRIVER = 2 V
sink current
Isink
VCC = 15 V
voltage on pin DRIVER = 2 V
voltage on pin DRIVER = 9.5 V
Vo(max)
[1]
maximum output voltage
VCC = 15 V
The VCC stop voltage is Vstartup  Vhys.
TEA1792T
Product data sheet
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GreenChip synchronous rectifier controller
11. Application information
A switched mode power supply with the TEA1792T consists of a primary side
discontinuous conduction mode flyback controller, a transformer and an output stage with
a feedback circuit. A MOSFET (Qsec) is used for low conduction losses in the output state.
The TEA1792T controls this MOSFET.
The timing for the synchronous rectifier switch is derived from the voltage sensed on the
SRSENSE pin. The resistor in the SRSENSE connection protects the TEA1792T from
excessive voltages. The RSRSENSE resistor is typically 1 k. Higher values can impair
correct timing, lower values do not provide sufficient protection.
TR
Qsec
Vo
VIN
RDRIVER
CVCC
GND
PRIMARY
SIDE
CONTROLLER
RSRSENSE
SELREG DRIVER
Qprim
Cout
TEA1792
VCC
SRSENSE
aaa-000138
Fig 4.
Application diagram high side rectification
TR
VIN
Vo
RSRSENSE
PRIMARY
SIDE
CONTROLLER
SRSENSE
VCC
Qprim Qsec
RDRIVER
Cout
TEA1792
DRIVER
SELREG
GND
aaa-000139
Fig 5.
TEA1792T
Product data sheet
Application diagram low side rectification
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GreenChip synchronous rectifier controller
12. Package outline
SO8: plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
D
E
A
X
c
y
HE
v M A
Z
5
8
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
1
L
4
e
detail X
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (2)
e
HE
L
Lp
Q
v
w
y
Z (1)
mm
1.75
0.25
0.10
1.45
1.25
0.25
0.49
0.36
0.25
0.19
5.0
4.8
4.0
3.8
1.27
6.2
5.8
1.05
1.0
0.4
0.7
0.6
0.25
0.25
0.1
0.7
0.3
inches
0.069
0.010 0.057
0.004 0.049
0.01
0.019 0.0100
0.014 0.0075
0.20
0.19
0.16
0.15
0.05
0.01
0.01
0.004
0.028
0.012
0.244
0.039 0.028
0.041
0.228
0.016 0.024
θ
8o
o
0
Notes
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included.
Fig 6.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT96-1
076E03
MS-012
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-18
Package outline SOT96-1 (SO8)
TEA1792T
Product data sheet
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GreenChip synchronous rectifier controller
13. Revision history
Table 6.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
TEA1792T v.2
20120709
Product data sheet
-
TEA1792T v.1.1
TEA1792T v.1.1
20120126
Objective data sheet
-
TEA1792T v.1
TEA1792T v.1
20110816
Objective data sheet
-
-
TEA1792T
Product data sheet
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14. Legal information
14.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
14.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
14.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information. NXP Semiconductors takes no
responsibility for the content in this document if provided by an information
source outside of NXP Semiconductors.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
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contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
TEA1792T
Product data sheet
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors and its suppliers accept no liability for
inclusion and/or use of NXP Semiconductors products in such equipment or
applications and therefore such inclusion and/or use is at the customer’s own
risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
All information provided in this document is subject to legal disclaimers.
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Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from competent authorities.
Non-automotive qualified products — Unless this data sheet expressly
states that this specific NXP Semiconductors product is automotive qualified,
the product is not suitable for automotive use. It is neither qualified nor tested
in accordance with automotive testing or application requirements. NXP
Semiconductors accepts no liability for inclusion and/or use of
non-automotive qualified products in automotive equipment or applications.
In the event that customer uses the product for design-in and use in
automotive applications to automotive specifications and standards, customer
(a) shall use the product without NXP Semiconductors’ warranty of the
product for such automotive applications, use and specifications, and (b)
whenever customer uses the product for automotive applications beyond
NXP Semiconductors’ specifications such use shall be solely at customer’s
own risk, and (c) customer fully indemnifies NXP Semiconductors for any
liability, damages or failed product claims resulting from customer design and
use of the product for automotive applications beyond NXP Semiconductors’
standard warranty and NXP Semiconductors’ product specifications.
14.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
GreenChip — is a trademark of NXP B.V.
15. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
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Product data sheet
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16. Contents
1
2
2.1
2.2
2.3
3
4
5
6
6.1
6.2
7
7.1
7.2
7.3
7.4
7.5
8
9
10
11
12
13
14
14.1
14.2
14.3
14.4
15
16
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features and benefits . . . . . . . . . . . . . . . . . . . . 1
Distinctive features . . . . . . . . . . . . . . . . . . . . . . 1
Green features . . . . . . . . . . . . . . . . . . . . . . . . . 1
Protection features . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pinning information . . . . . . . . . . . . . . . . . . . . . . 3
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3
Functional description . . . . . . . . . . . . . . . . . . . 4
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Start-up and UnderVoltage LockOut (UVLO) . . 4
Synchronous rectification . . . . . . . . . . . . . . . . . 4
Supply management. . . . . . . . . . . . . . . . . . . . . 5
Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 6
Thermal characteristics . . . . . . . . . . . . . . . . . . 6
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Application information. . . . . . . . . . . . . . . . . . . 8
Package outline . . . . . . . . . . . . . . . . . . . . . . . . . 9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . 10
Legal information. . . . . . . . . . . . . . . . . . . . . . . 11
Data sheet status . . . . . . . . . . . . . . . . . . . . . . 11
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Contact information. . . . . . . . . . . . . . . . . . . . . 12
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2012.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 9 July 2012
Document identifier: TEA1792T