TEA1732TS
GreenChip SMPS control IC
Rev. 1 — 18 March 2014
Product data sheet
1. General description
The TEA1732TS is a low cost Switched Mode Power Supply (SMPS) controller IC
intended for flyback topologies. The TEA1732TS operates in peak current and frequency
control mode. Frequency jitter has been implemented to reduce ElectroMagnetic
Interference (EMI). Slope compensation is integrated for Continuous Conduction Mode
(CCM) operation.
The TEA1732TS IC features OverPower Protection (OPP). The controller accepts an
overpower situation for a limited amount of time.
Mains undervoltage protection (brownout), output OverVoltage Protection (OVP), and
OverTemperature Protection (OTP) can be implemented using a minimal number of
external components.
At low-power levels, the primary peak current is set to 25 % of the maximum peak current.
The switching frequency is reduced to limit the switching losses. The combination of fixed
frequency operation at high output power and frequency reduction at low output power
provides high efficiency over the total load range.
The TEA1732TS makes the design of low-cost, highly efficient and reliable supplies for
power requirements up to 75 W easier by requiring a minimum number of external
components.
2. Features and benefits
SMPS controller IC enabling low-cost applications
Large input voltage range (12 V to 30 V)
Integrated OverVoltage Protection (OVP) on the VCC pin
Accurate OverVoltage Protection (OVP) via the ISENSE pin
Very low supply current during start-up and restart (10
A
typical)
Low supply current during normal operation (0.58 mA typical without load)
Internal overpower time-out
Overpower protection or high/low line compensation
Fixed switching frequency with frequency jitter to reduce EMI
Frequency reduction with fixed minimum peak current to maintain high efficiency at
low output power levels
Frequency increase at peak power operation
Slope compensation for CCM operation
Integrated soft-start
NXP Semiconductors
TEA1732TS
GreenChip SMPS control IC
Low and adjustable OverCurrent Protection (OCP) trip level
Mains undervoltage protection (brownout)
External OverTemperature Protection (OTP)
IC overtemperature protection
3. Applications
All applications that require an efficient and cost-effective power supply solution up to
75 W.
4. Ordering information
Table 1.
Ordering information
Package
Name
TEA1732TS/1
TSOP6
Description
plastic surface-mounted package; 6 leads
Version
SOT457
Type number
5. Block diagram
Fig 1.
TEA1732TS block diagram
TEA1732TS
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet
Rev. 1 — 18 March 2014
2 of 20
NXP Semiconductors
TEA1732TS
GreenChip SMPS control IC
6. Pinning information
6.1 Pinning
Fig 2.
TEA1732TS pin configuration
6.2 Pin description
Table 2.
Symbol
VCC
GND
PROTECT
CTRL
ISENSE
DRIVER
Pin description
Pin
1
2
3
4
5
6
Description
supply voltage
ground
protection and mains detect input
control input
current sense and accurate OVP input
gate driver output
7. Functional description
7.1 General control
The TEA1732TS contains a controller for a flyback circuit. A typical configuration is shown
in
Figure 3.
TEA1732TS
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© NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet
Rev. 1 — 18 March 2014
3 of 20
NXP Semiconductors
TEA1732TS
GreenChip SMPS control IC
Fig 3.
TEA1732TS typical configuration
7.2 Start-up and UnderVoltage LockOut (UVLO)
Initially, the capacitor on the VCC pin, C3, is charged from the high-voltage mains via
resistor R1.
As long as VCC is below V
startup
, the IC current consumption is low (10
A
typical). When
VCC reaches V
startup
, the IC first waits for the mains voltage to exceed the brownin level,
and the PROTECT pin to reach the V
det(PROTECT)(L)
voltage. When both conditions are
met, the IC starts switching. An internal soft-start time of 3.5 ms allows the ISENSE peak
voltage to increase gradually to prevent audible noise. In a typical application, the
auxiliary winding of the transformer takes over the supply voltage.
If a protection is triggered, the controller stops switching. Depending on the protection
triggered, it either causes a restart or latches the converter to an off-state.
The OPP, UVLO, brownout, and maximum duty cycle protections cause a save restart.
The OVP, external OTP, and internal OTP protections latch the converter to an off-state.
A restart protection disables the switching of the IC. The supply voltage of the IC drops to
the UVLO level. When the UVLO level is reached, the IC switches to Power-down mode,
where it consumes a low supply current (10
A
typical). The VCC capacitor is recharged
via R1 until the VCC start-up level is reached. A delayed restart is performed to lower the
average input power during a fault condition. Depending on the cause of the restart
protection, the restart sequence that discharges and recharges the VCC capacitor is
performed once or repeated three times, before switching recommences (See
Figure 4).
When a latched protection is triggered, the TEA1732TS immediately enters Power-down
mode. The VCC pin is clamped to a voltage just above the latch protection reset voltage
(V
rst(latch)
+ 0.9 V).
TEA1732TS
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet
Rev. 1 — 18 March 2014
4 of 20
NXP Semiconductors
TEA1732TS
GreenChip SMPS control IC
Fig 4.
Start-up sequence, normal operation and restart sequence
When the voltage on pin VCC drops below the V
th(UVLO)
level during normal operation, the
controller stops switching. The TEA1732TS waits for the rectified mains to charge the
VCC pin using resistor R1.
7.3 Supply management
All internal reference voltages are derived from a temperature compensated on-chip band
gap circuit. Internal reference currents are derived from a trimmed and temperature
compensated current reference circuit.
7.4 External overtemperature protection and mains detect input
(pin PROTECT)
The PROTECT input combines the functions of the external OverTemperature Protection
(OTP) and the mains voltage detection. An internal clock separates the period of
measuring the mains voltage and the period of detecting external OverTemperature
Protection (OTP). In a typical application, the PROTECT pin is connected to the mains via
a resistor and to ground via a negative temperature coefficient (NTC) thermistor and a
diode.
When measuring the mains voltage, the PROTECT pin is regulated to 0.25 V so that the
external diode does not conduct any current. The current into the PROTECT pin is
measured and stored. Once the measured current is above the brownin level, the system
is allowed to start switching. If the mains voltage is continuously below the brownout level
for at least 32 ms, a brownout is detected. The system immediately stops switching and
performs a restart. The VCC capacitor is discharged to the UVLO level and then charged
to V
startup
once before switching recommences (See
Figure 5).
TEA1732TS
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet
Rev. 1 — 18 March 2014
5 of 20
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