TEA1705
GreenChip SMPS transient controller
Rev. 2 — 12 December 2013
Product data sheet
1. General description
The TEA1705 is a secondary side IC to be used in Switched Mode Power Supplies
(SMPS) with high power density. The device offers excellent transient response in primary
controlled systems of NXP Semiconductors, with ultra-low no-load power and minimum
sized output capacitors. The TEA1705 is intended to be used in power supplies and
battery chargers with 5 V output. The TEA1705 operates in combination with the NXP
Semiconductors primary-side controller like the TEA1720xT. The output voltage is
continuously monitored and when the output voltage is below the V
det
level, a transient
interrupt signal is generated. This signal is transmitted via the transformer to the primary
side to wake up the primary controller. This system reduces the volume of the output
capacitors, minimizing the BOM cost. It also enables the building of compact chargers.
2. Features and benefits
Excellent transient performance with ultra-low no-load power and smallest output
capacitors
Fast detection of a decreasing output voltage during load steps
Integrated output voltage clamp function
Device available in small SOT23 package
3. Applications
Battery chargers for smart phones and media tablets
Standby supply for TV and desktop PC
4. Ordering information
Table 1.
Ordering information
Package
Name
TEA1705/1
TO-236AB
Description
plastic surface-mounted package; 3 leads
Version
SOT23
Type number
NXP Semiconductors
TEA1705
GreenChip SMPS transient controller
5. Marking
Table 2.
TEA1705
[1]
% = placeholder for manufacturing site code
Marking codes
Marking code
[1]
%4U
Type number
6. Block diagram
Fig 1.
TEA1705 block diagram
7. Pinning information
7.1 Pinning
3
1
2
006aaa144
Fig 2.
TEA1705 pin configuration
TEA1705
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 2 — 12 December 2013
2 of 11
NXP Semiconductors
TEA1705
GreenChip SMPS transient controller
7.2 Pin description
Table 3.
Symbol
VCC
CAP
GND
Pin description
Pin
1
2
3
Description
supply voltage
connection for communication capacitor
ground
8. Functional description
8.1 Start-up
The TEA1705 starts up when a supply voltage is applied to the VCC pin. When the VCC
voltage exceeds the V
startup
level the IC is enabled. The IC stays in this mode until the
VCC voltage drops below the V
CC(stop)
level. All detection voltages on the VCC pin are
derived from an integrated temperature compensated band gap voltage.
8.2 Detection
During the switching of the primary controller in the flyback application, the capacitor
connected between the secondary winding of the transformer and the CAP pin is charged.
The capacitor is charged using the body diode of the integrated switch. The switching of
the primary side is monitored using a circuit on the CAP pin of the TEA1705.
When the switching has stopped for t
blank
and the monitored VCC voltage is lower than
the V
det
level, the integrated switch is turned on for a duration of t
on
. The external
capacitor discharges through the secondary transformer winding. On the primary side of
the transformer a wake-up pulse is detected by using a primary control IC like the
TEA1720xT. The primary IC exits the energy save state and starts to deliver output power.
8.3 MOSFET-switch
Generating the transient interrupt signal is enabled by using an internal MOSFET-switch
between the CAP and GND pins to discharge the external capacitor. The integrated body
diode of this switch is used to charge the external capacitor when the primary switch in the
flyback application is switching again.
8.4 Clamp
An integrated clamp function is present on the VCC pin. If the voltage on the VCC pin
exceeds V
clamp(VCC)
, the clamp circuit drains away the current. The clamp circuit has an
impedance of R
clamp
. It helps to prevent an overvoltage on the output capacitors.
TEA1705
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 2 — 12 December 2013
3 of 11
NXP Semiconductors
TEA1705
GreenChip SMPS transient controller
9. Limiting values
Table 4.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).All voltages are measured
with respect to GND; positive currents flow into the IC. The voltage ratings and current ratings are
valid provided the other ratings are not violated.
Symbol
Voltages
V
CC
V
CAP
Currents
I
CC
I
CAP
supply current
current on pin CAP
Repetitive;
pulse width
1
s;
repetition time
50
s
Non-repetitive;
pulse width
1
s
General
T
stg
T
j
V
ESD
storage temperature
junction temperature
electrostatic discharge
voltage
human body model
[1]
Charged device model
-55
40
2000
500
+150
+150
+2000
+500
C
C
V
V
0
2.5
50
+2.5
mA
A
supply voltage
voltage on pin CAP
0.3
-
+7
+50
V
V
Parameter
Conditions
Min
Max
Unit
3.5
-
A
[1]
Equivalent to discharging a 100 pF capacitor through a 1.5 k series resistor.
10. Thermal characteristics
Table 5.
Symbol
R
th(j-a)
[1]
Thermal characteristics
Parameter
thermal resistance from junction
to ambient
Conditions
in free air
[1]
Typ
300
Unit
K/W
Device mounted on an FR-4 Printed-Circuit Board (PCB), single-sided copper, tin-plated and standard
footprint.
TEA1705
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 2 — 12 December 2013
4 of 11
NXP Semiconductors
TEA1705
GreenChip SMPS transient controller
11. Characteristics
Table 6.
Characteristics
V
CC
= 5 V; T
amb
= 25
C; all voltages referenced to GND; positive currents flow into the IC, unless otherwise specified.
Symbol
I
leak(CAP)
V
startup
V
CC(stop)
V
CC(hys)
I
CC
Parameter
leakage current on pin CAP
start-up voltage
stop supply voltage
hysteresis of supply voltage
supply current
V
CC(hys)
= V
startup
V
CC(stop)
V
CC
= 5.5 V; current decreases slightly
at lower supply voltages
Conditions
V
CAP
= 50 V
Min
-
4.3
3.9
0.35
85
Typ
-
4.4
4.0
0.4
97
Max
1
4.5
4.1
0.45
110
Unit
A
V
V
V
A
High voltage (pin CAP)
Supply (pin VCC)
Detection (pin VCC)
V
det
t
on
R
on
t
blank
detection voltage
on-time
on-state resistance
blanking time
I
CAP
= 100 mA
V
CC
= 4.8 V; after last primary stroke
clamp start voltage; I
VCC
= 1 mA
differential measurement between
V
CC
= 7 V and V
CC
= V
clamp(VCC)
4.8
-
-
-
5.80
-
4.9
1.1
2
65
5.92
26
5.0
-
-
-
6.05
-
V
s
s
V
Switch (pin CAP)
Timer (pin CAP)
Clamp (pin VCC)
V
clamp(VCC)
clamp voltage on pin VCC
R
clamp
clamp resistance
TEA1705
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 2 — 12 December 2013
5 of 11
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