TEA1791T [NXP]
GreenChip synchronous rectifier controller; 的GreenChip同步整流器器控制器
| 型号： | TEA1791T |
| 厂家： | 
NXP |
| 描述： | GreenChip synchronous rectifier controller |
| 文件： | 总11页 (文件大小：64K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TEA1791T
GreenChip synchronous rectifier controller
Rev. 01 — 3 February 2009
Product data sheet
1. General description
The TEA1791T 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 TEA1791T is a controller IC dedicated for synchronous rectification on the secondary
side of discontinuous conduction mode and quasi-resonant flyback converters.
The TEA1791T is fabricated in a Silicon On Insulator (SOI) process.
2. Features
2.1 Distinctive features
I Accurate synchronous rectification functionality
I Wide supply voltage range (8.5 V to 38 V)
I High level of integration, resulting in a very low external component count
I High driver output voltage of 10 V to drive all MOSFET brands to the lowest RDSon
2.2 Green features
I Low current consumption
I High system efficiency from no load to full load
2.3 Protection features
I Undervoltage protection
3. Applications
I The TEA1791T 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.
4. Ordering information
Table 1.
Ordering information
Type number
Package
Name
Description
Version
TEA1791T/N1
SO8
plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
5. Block diagram
V
CC
8
1
4
SRSENSE
control
Q R
TIMER
2 µs
DRIVER
Q S
2.2µs
−310 mV
−12 mV
−55 mV
3, 5, 6, 7
n.c.
2
GND
014aaa700
Fig 1. Block diagram
6. Pinning information
6.1 Pinning
1
8
7
6
5
SRSENSE
V
CC
2
3
4
GND
n.c.
n.c.
n.c.
n.c.
TEA1791T
DRIVER
014aaa701
Fig 2. Pin configuration
6.2 Pin description
Table 2.
Symbol
SRSENSE
GND
Pin description
Pin
1
Description
synchronous timing input
ground
2
n.c.
3
not connected
DRIVER
n.c
4
driver output for SR MOSFET
not connected
5
n.c.
6
not connected
n.c.
7
not connected
VCC
8
supply voltage
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
2 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
7. Functional description
7.1 Introduction
The TEA1791T is the controller for synchronous rectification to be 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 as soon as the voltage on the VCC pin is above 8.5 V (typ). As soon as the voltage
drops below 8.0 V (typ), the undervoltage lockout state is reentered and the SR driver
output is actively kept low.
7.3 Synchronous rectification
After a negative voltage (−310 mV typ) is sensed on the SRSENSE pin, the driver output
voltage is driven HIGH and the external MOSFET is switched on. As soon as the
SRSENSE voltage rises to −55 mV the driver output voltage is regulated to maintain the
−55 mV on the SRSENSE pin. As soon as the SRSENSE voltage is above −12 mV, the
driver output is pulled to ground.
After switch-on of the SR MOSFET, the input signal on the SRSENSE pin is blanked for
2 µs (typ). This eliminates false switch-off due to high frequency ringing at the start of the
secondary stroke.
Because the driver output voltage is reduced as soon as the voltage on the SRSENSE pin
is −55 mV, the external power switch can be switched off quickly when the current through
the switch reaches zero. With this zero current switch-off, no separate standby mode is
needed to maintain high efficiency during the no-load operation. The zero current is
detected by sensing a −12 mV level on the SRSENSE pin (see Figure 3).
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
3 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
V
SRSENSE
0 V
−12 mV
−55 mV
−310 mV
Primary
current
0 A
Secondary
current
0 A
V
DRIVER
0 V
014aaa057
Fig 3. Synchronous rectification signals
If the secondary stroke of the flyback converter is shorter than 2 µs (typ), the driver output
is disabled. This will guarantee stable operation for very low duty cycles. When the
secondary stroke increases above 2.2 µs (typ), 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 gate of the external power MOSFET has a source capability of
typically 250 mA and a sink capability of typically 2.7 A. This permits fast turn-on and
turn-off of the power MOSFET for efficient operation. The output voltage of the driver is
limited to 10 V (typical). This high output voltage will drive 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.
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
4 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
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 are valid
provided other ratings are not violated; current ratings are valid provided the other ratings are not
violated.
Symbol
Voltages
VCC
Parameter
Conditions
Min
Max
Unit
supply voltage
continuous
continuous
−0.4
+38
120
V
V
VSRSENSE voltage on pin SRSENSE
-
Currents
IDRIVER
ISRSENSE
General
Ptot
current on pin DRIVER
current on pin SRSENSE
duty cycle < 10 %
Tamb < 80 °C
class 2
−0.8
−3
+3
-
A
mA
total power dissipation
storage temperature
junction temperature
-
0.45
W
Tstg
−55
−20
+150
+150
°C
°C
Tj
Vesd
electrostatic discharge
voltage
[1]
[2]
human body
model
-
2000
V
machine model
-
-
200
500
V
V
charged device
model
[1] Equivalent to discharging a 100 pF capacitor through a 1.5 kΩ series resistor.
[2] Equivalent to discharging a 200 pF capacitor through a 0.75 µH coil and a 1.5 kΩ series resistor.
9. Thermal characteristics
Table 4.
Thermal characteristics
Parameter
Symbol
Conditions
Typ
Unit
Rth(j-a)
thermal resistance from junction in free air
to ambient
150
K/W
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
5 of 11
TEA1791T
NXP Semiconductors
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
Supply voltage management (pin VCC
)
Vstartup
Vhys
start-up voltage
8.2
8.5
8.8
V
[1]
hysteresis voltage
-
-
-
0.5
-
-
-
V
ICC(oper)
operating supply current VCC = 8 V (VCC < Vstartup
)
0.65
0.95
mA
mA
under normal operation; no
load on pin DRIVER
Synchronous rectification sense input (pin SRSENSE)
Vact(drv)
Vreg(drv)
driver activation voltage
driver regulation voltage
−340
−65
-
−310
−55
−280
−45
-
mV
mV
mV
Vdeact(drv) driver deactivation
voltage
−12
td(act)(drv)
driver activation delay
time
-
125
-
ns
tact(sr)(min) minimum synchronous
rectification active time
Short time
Long time
1.5
1.7
2.0
2.2
2.5
2.7
µs
µs
Driver (pin DRIVER)
Isource
source current
VCC = 15 V; voltage on pin
DRIVER = 2 V
−0.3
−0.25
−0.2
A
Isink
sink current
VCC = 15 V
voltage on pin DRIVER = 2 V
1
1.4
2.7
-
-
A
A
voltage on pin
2.2
DRIVER = 9.5 V
Vo(max)
maximum output voltage VCC = 15 V
-
10
12
V
[1] The VCC stop voltage is Vstartup − Vhys
.
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
6 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
11. Application information
A switched mode power supply with the TEA1791T consists of a primary side
discontinuous conduction mode flyback controller, a transformer, and an output stage with
a feedback circuit. In the output stage a MOSFET (Qsec) is used for low conduction
losses. The MOSFET is controlled by the TEA1791T.
The timing for the synchronous rectifier switch is derived from the voltage sensed on the
SRSENSE pin. The resistor in the SRSENSE connection is needed to protect the
TEA1791T from excessive voltages. The SRSENSE resistor should typically be 1 kΩ.
Higher values might impair correct timing, lower values may not provide sufficient
protection.
TR
Qsec
V
out
R
SRSENSE
V
in
GND DRIVER
C
out
Q
prim
TEA1791T
PRIMARY
SIDE
CONTROLLER
V
CC
SRSENSE
014aaa702
Fig 4. Application diagram
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
7 of 11
TEA1791T
NXP Semiconductors
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
v
c
y
H
M
A
E
Z
5
8
Q
A
2
A
(A )
3
A
1
pin 1 index
θ
L
p
L
1
4
e
w
M
detail X
b
p
0
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
A
(1)
(1)
(2)
UNIT
A
A
A
b
c
D
E
e
H
L
L
p
Q
v
w
y
Z
θ
1
2
3
p
E
max.
0.25
0.10
1.45
1.25
0.49
0.36
0.25
0.19
5.0
4.8
4.0
3.8
6.2
5.8
1.0
0.4
0.7
0.6
0.7
0.3
mm
1.27
0.05
1.05
0.041
1.75
0.25
0.01
0.25
0.01
0.25
0.1
8o
0o
0.010 0.057
0.004 0.049
0.019 0.0100 0.20
0.014 0.0075 0.19
0.16
0.15
0.244
0.228
0.039 0.028
0.016 0.024
0.028
0.012
inches 0.069
0.01 0.004
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.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
JEITA
99-12-27
03-02-18
SOT96-1
076E03
MS-012
Fig 5. Package outline SOT96-1 (SO8)
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
8 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
13. Revision history
Table 6.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
TEA1791T_1
20090203
Product data sheet
-
-
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
9 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
14. Legal information
14.1 Data sheet status
Document status[1][2]
Product status[3]
Development
Definition
Objective [short] data sheet
This document contains data from the objective specification for product development.
This document contains data from the preliminary specification.
This document contains the product specification.
Preliminary [short] data sheet Qualification
Product [short] data sheet Production
[1]
[2]
[3]
Please consult the most recently issued document before initiating or completing a design.
The term ‘short data sheet’ is explained in section “Definitions”.
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.
damage. NXP Semiconductors accepts 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.
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.
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.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) may cause permanent
damage to the device. Limiting values are stress ratings only and operation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
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.
Terms and conditions of 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, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
14.3 Disclaimers
General — 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.
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.
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.
Quick reference data — The Quick reference data is an extract of the
product data given in the Limiting values and Characteristics sections of this
document, and as such is not complete, exhaustive or legally binding.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support 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
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: salesaddresses@nxp.com
TEA1791T_1
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 01 — 3 February 2009
10 of 11
TEA1791T
NXP Semiconductors
GreenChip synchronous rectifier controller
16. Contents
1
General description . . . . . . . . . . . . . . . . . . . . . . 1
2
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Distinctive features . . . . . . . . . . . . . . . . . . . . . . 1
Green features . . . . . . . . . . . . . . . . . . . . . . . . . 1
Protection features . . . . . . . . . . . . . . . . . . . . . . 1
2.1
2.2
2.3
3
4
5
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ordering information. . . . . . . . . . . . . . . . . . . . . 1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
6
6.1
6.2
Pinning information. . . . . . . . . . . . . . . . . . . . . . 2
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 2
7
Functional description . . . . . . . . . . . . . . . . . . . 3
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Start-up and UnderVoltage LockOut (UVLO) . . 3
Synchronous rectification . . . . . . . . . . . . . . . . . 3
Supply management. . . . . . . . . . . . . . . . . . . . . 4
Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1
7.2
7.3
7.4
7.5
8
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 5
Thermal characteristics. . . . . . . . . . . . . . . . . . . 5
Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 6
Application information. . . . . . . . . . . . . . . . . . . 7
Package outline . . . . . . . . . . . . . . . . . . . . . . . . . 8
Revision history. . . . . . . . . . . . . . . . . . . . . . . . . 9
9
10
11
12
13
14
Legal information. . . . . . . . . . . . . . . . . . . . . . . 10
Data sheet status . . . . . . . . . . . . . . . . . . . . . . 10
Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 10
14.1
14.2
14.3
14.4
15
16
Contact information. . . . . . . . . . . . . . . . . . . . . 10
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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. 2009.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
Date of release: 3 February 2009
Document identifier: TEA1791T_1
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