AN11675
GreenChip TEA1833(L)TS fixed frequency flyback controller
Rev. 1 — 20 July 2015
Application note
Document information
Info
Keywords
Abstract
Content
GreenChip, TEA1833(L)TS, SMPS, flyback, adapter, notebook, ultralight
notebook, LCD TV, LCD monitors
The TEA1833(L)TS is a low-cost member of the GreenChip family in a
very small package. It is a fixed-frequency flyback controller, especially
suited for medium-power applications, such as ultralight notebook,
notebooks, printers, LCD TVs, and LCD monitors.
No-load power can be as low as 55 mW at 230 V (AC).
Delivery of 200 % peak power for short periods is possible.
Because of a reduced switching frequency, efficiency also remains high at
low load.
NXP Semiconductors
AN11675
GreenChip TEA1833(L)TS fixed frequency flyback controller
Revision history
Rev
v.1
Date
20150720
Description
first issue
Contact information
For more information, please visit:
http://www.nxp.com
For sales office addresses, please send an email to:
salesaddresses@nxp.com
AN11675
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2015. All rights reserved.
Application note
Rev. 1 — 20 July 2015
2 of 50
NXP Semiconductors
AN11675
GreenChip TEA1833(L)TS fixed frequency flyback controller
1. General description
The TEA1833(L)TS is a fixed-frequency flyback controller that can be used for
Discontinuous Conduction Mode (DCM) and Continuous Conduction Mode (CCM).
Despite the very small TSOP6 package, it almost has the full functionality of the TEA1738
series.
1.1 Scope
This application note describes the functionality of the TEA1833(L)TS series.
Fixed-frequency flyback fundamentals and calculation of transformer and other large
signal parts are not dealt with in this document.
1.2 Features
1.2.1 Power features
•
SMPS controller IC enabling low-cost applications
•
Small low-cost TSOP6 package
•
Fixed switching frequency with frequency jitter to reduce ElectroMagnetic Interference
(EMI)
•
Frequency reduction with fixed minimum peak current to maintain high efficiency and
low output ripple at low-power output levels
•
Peak power operation in CCM, increased peak current (1.4 times) and switching
frequency (2 times)
•
•
•
•
Slope compensation for CCM operation
Integrated soft start
High/low line compensation for constant overpower protection level
Wide V
CC
voltage range (10.5 V to 36 V)
1.2.2 Green features
•
No-load power consumption < 55 mW at 230 V (AC) possible for 65 W applications.
•
Very low supply current during start and restart (11
A
typical) enabling the use of a
high-ohmic start-up resistor.
•
Burst mode when the voltage on the VCC pin drops to the burst threshold level (just
above UnderVoltage LockOut (UVLO) level) to prevent a restart during prolonged no
switching. It enables using a small V
CC
capacitor and a high-ohmic start-up resistor.
•
Low supply current during normal operation (0.58 mA typical).
•
Frequency reduction at low load to maintain high efficiency at low load
AN11675
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2015. All rights reserved.
Application note
Rev. 1 — 20 July 2015
3 of 50
NXP Semiconductors
AN11675
GreenChip TEA1833(L)TS fixed frequency flyback controller
1.2.3 Protection features
•
•
•
•
•
•
•
Accurate OverVoltage Protection (OVP) via the ISENSE pin
OverVoltage Protection on the VCC supply pin
UnderVoltage LockOut (UVLO) on the VCC supply pin
Internal OverTemperature Protection (OTP)
External OverTemperature Protection (OTP) using 100 k NTC resistor
Overpower time-out: 27.5 ms (TEA1833TS); 160 ms (TEA1833LTS)
Overpower time-out during output short circuit conditions, reducing the average input
power: 14.5 ms (TEA1833TS only)
and short circuit (TEA1833TS only)
•
Restart timer after an overpower condition for low average input power at overload
•
Output Short Circuit Protection (OSCP) to prevent transformer saturation during
start-up, overload events or short circuit events
•
Maximum frequency limitation at high mains to prevent unnecessary high voltage on
drain of MOSFET
•
Brownin and brownout protection to avoid operation during mains undervoltage
conditions
•
Maximum duty cycle protection for
> 90 %
1.3 Applications
The TEA1833(L)TS is intended for applications that require an efficient and cost-effective
power supply solution. It is especially suited for medium-power applications like:
•
Ultrabooks and notebooks
•
LCD TVs and LCD monitors
•
Printers
1.4 Differences between the TEA1833 and the TEA1738 series
•
Smaller package (TSOP6):
•
The VINSENSE pin has been removed. The functionality has been combined on the
PROTECT pin with the external overtemperature protection.
•
The OPTIMER pin has been removed. The functionality has been integrated:
–
Internal overpower time-out: 27.5 ms (TEA1833TS); 160 ms (TEA1833LTS);
external timing components no longer required.
–
Internal restart timer; extra external components for time constant no longer
required.
•
Increased rating of the VCC clamp (1 mA instead of 730
A).
•
Extra filtering on latched protections:
–
Latched protection can only be triggered if a fault condition lasts at least four
consecutive switching cycles or measuring cycles (external OTP).
–
Low-pass filtering provides immunity against high-frequency signals, for example,
from mobile phones.
AN11675
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2015. All rights reserved.
Application note
Rev. 1 — 20 July 2015
4 of 50
NXP Semiconductors
AN11675
GreenChip TEA1833(L)TS fixed frequency flyback controller
•
Fixed frequency operation with frequency jitter for simple EMI filtering (no frequency
reduction for lower power).
•
Maximum duty cycle protection modified:
In the TEA1738 series, the maximum on-time protection is only active during peak
power conditions (V
ctrl(Ipeak)
> 400 mV). This restriction has been removed because of
the new frequency control implementation. The maximum duty cycle is increased from
80 % to 90 %.
•
VCC range increased to 10.5 V to 36 V (was 12 V to 30 V).
•
New features:
–
Burst mode when the voltage on the VCC pin drops to below the burst threshold
level (just above UVLO) preventing restart during prolonged no switching. It
enables using a small VCC capacitor and a high-ohmic start-up resistor.
–
Output Short Circuit Protection (OSCP) to prevent transformer saturation at
start-up, overload events, and short circuit events.
1.5 Differences between the TEA1833 and the TEA1733 series
•
Smaller package (TSOP6):
•
The VINSENSE pin has been removed. The functionality has been partly combined
on the PROTECT pin with the external OTP. The mains OVP function does not exist in
the TEA1833(L)TS anymore:
•
The OPTIMER pin has been removed. The functionality has been integrated:
–
Internal overpower time-out: 27.5 ms (TEA1833TS); 160 ms (TEA1833LTS);
external timing components no longer required
–
Internal restart timer; extra external components for time constant no longer
required
•
Internal OverVoltage Protection (OVP) added. If the VCC pin exceeds 36 V, the
latched protection mode is triggered
•
Increased rating of the VCC clamp (1 mA instead of 240
A)
•
Extra filtering on latched protections:
–
Latched protection can only be triggered if a fault condition lasts at least four
consecutive switching cycles or measuring cycles (external OTP)
–
Low-pass filtering provides immunity against high-frequency signals; for example,
from mobile phones
•
Maximum duty cycle protection added; when 8 cycles
> 90 %, the restart protection
is activated
•
Fixed frequency operation with frequency jitter for simple EMI filtering (no frequency
reduction for lower power, as with the TEA1733)
•
Increased switching frequency during peak load allowing more output power with the
same core
•
New features:
–
Burst mode when the voltage on the VCC pin drops to below the burst threshold
level (just above UVLO) preventing restart during prolonged no switching. It
enables using a small VCC capacitor and a high-ohmic start-up resistor
AN11675
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2015. All rights reserved.
Application note
Rev. 1 — 20 July 2015
5 of 50
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