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TEA1738T/N1,118

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21
TEA1738T_TEA1738LT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 14 January 2011 10 of 21
NXP Semiconductors
TEA1738T; TEA1738LT
GreenChip SMPS control IC
7.12 Soft start-up (ISENSE pin)
A soft start is performed to prevent audible noise during start-up or a restart condition.
Before the converter (re)starts, soft start capacitor C6 (see Figure 3
) on the ISENSE pin is
charged. When the converter (re)starts switching, the primary peak current slowly
increases as the soft start capacitor discharges through the soft start resistor (R6, see
Figure 3
).
The soft start time constant is set by the soft start capacitor value chosen. The soft start
resistor value must also be taken into account, but this value is typically defined by the
overpower compensation (see Section 7.11
).
7.13 Peak power, medium power and low power operation
The switching frequency is increased for peak power operation. In medium power
operation the switching losses are reduced by lowering the switching frequency. A second
frequency reduction step is made when the output power is reduced to low power. In low
power operation the converter switching frequency is reduced while the peak current is
set to 25 % of the maximum peak current (see Figure 7
and Figure 10).
Fig 9. Overpower compensation
2
1.7
0.68 1234
014aaa93
3
I
ISENSE
(μA)
V
VINSENSE
(V)
Fig 10. Frequency control
f
osc
V
CTRL
014aab2
94
2
1
3
medium
power
high
power
low power
peak power
28 kHz
66 kHz
80 kHz
TEA1738T_TEA1738LT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 14 January 2011 11 of 21
NXP Semiconductors
TEA1738T; TEA1738LT
GreenChip SMPS control IC
7.14 Driver (pin DRIVER)
The driver circuit to the gate of the power MOSFET has a current sourcing capability of
typically 300 mA and a current sink capability of typically 750 mA. This allows for a fast
turn-on and turn-off of the power MOSFET for efficient operation.
7.15 OverTemperature Protection (OTP)
Integrated temperature protection ensures the IC stops switching if the junction
temperature exceeds the thermal shutdown temperature limit.
OTP is a latched protection. It can be reset by removing the voltage on pin VCC.
8. Limiting values
Table 3. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter Conditions Min Max Unit
Voltages
V
CC
supply voltage continuous −0.4 +30 V
t < 100 ms - 35 V
V
VINSENSE
voltage on pin VINSENSE current limited −0.4 +5.5 V
V
PROTECT
voltage on pin PROTECT current limited −0.4 +5 V
V
CTRL
voltage on pin CTRL −0.4 +5.5 V
V
IO(OPTIMER)
input/output voltage on pin
OPTIMER
−0.4 +5 V
V
ISENSE
voltage on pin ISENSE current limited −0.4 +5 V
Currents
I
CC
supply current δ <10% - 0.4 A
I
I(VINSENSE)
input current on pin
VINSENSE
−1+1mA
I
I(PROTECT)
input current on pin
PROTECT
−1+1mA
I
CTRL
current on pin CTRL −30 mA
I
ISENSE
current on pin ISENSE −10 +1 mA
I
DRIVER
current on pin DRIVER δ <10% −0.4 +1 A
General
P
tot
total power dissipation T
amb
<75°C-0.5W
T
stg
storage temperature −55 +150 °C
T
j
junction temperature −40 +150 °C
TEA1738T_TEA1738LT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 14 January 2011 12 of 21
NXP Semiconductors
TEA1738T; TEA1738LT
GreenChip SMPS control IC
[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 10 Ω resistor.
9. Thermal characteristics
10. Characteristics
ESD
V
ESD
electrostatic discharge
voltage
class 1
human body
model
[1]
-4000V
machine model
[2]
-300V
charged device
model
-750V
Table 3. Limiting values …continued
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter Conditions Min Max Unit
Table 4. Thermal characteristics
Symbol Parameter Conditions Typ Unit
R
th(j-a)
thermal resistance from
junction to ambient
in free air;
JEDEC test board
150 K/W
R
th(j-c)
thermal resistance from
junction to case
in free air;
JEDEC test board
79 K/W
Table 5. Characteristics
T
amb
=25
°
C; V
CC
= 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)
V
startup
start-up voltage 18.6 20.6 22.6 V
V
th(UVLO)
undervoltage lockout
threshold voltage
11.2 12.2 13.2 V
V
th(ovp)
overvoltage protection
threshold voltage
29 30 31 V
N
cy(ovp)
number of overvoltage
protection cycles
7- 8
V
clamp(VCC)
clamp voltage on pin
VCC
activated during restart;
I
CC
=100μA
-V
startup
+1 - V
activated during latched
protection; I
CC
=100μA
-V
rst(latch)
+1 - V
activated during latched
protection; I
CC
=500μA
-- V
rst(latch)
+4 V
I
clamp(VCC)
clamp current on pin
VCC
activated during restart;
V
CC
=25V
730 - - μA
V
hys
hysteresis voltage V
startup
− V
th(UVLO)
7.5 9 10.5 V
I
CC(startup)
start-up supply current V
CC
<V
startup
510 15 μA
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21

TEA1738T/N1,118

Mfr. #:
Buy TEA1738T/N1,118
Manufacturer:
NXP Semiconductors
Description:
Switching Controllers GREENCHIP SMPS CONTROL IC
Lifecycle:
New from this manufacturer.
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