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TEA2261/0
SWITCH MODE POWER SUPPLY CONTROLLER
Positive and Negative Current up to 1.2A and 2A s Low Start-Up Current s Direct Drive of the Power Transistor s Two Levels Transistor Current Limitation s Double Pulse Suppression s Soft-Starting s Under and Overvoltage Lock-out s Automatic Stand-By Mode Recognition s Large Power Range Capability in Stand-By (Burst Mode) s Internal PWM Signal Generator DESCRIPTION The TEA2260/61 is a monolithic integrated circuit for the use in primary part of an off-line switching mode power supply. All functions required for SMPS control under normal operating, transient or abnormal conditions are provided. The capability of working according to the "master-slave" concept, or according to the "primary regulation" mode makes the TEA2260/61 very flexible and easy to use. This is particularly true for TV receivers where the IC provides an attractive and low cost solution (no need of stand-by auxiliary power supply). See application note AN376/ 0490 for detailed information.
s
BATWING DIP16 (Plastic Package) ORDER CODES: TEA2261/0
Figure 1. Pin Connections
TRANSFORMER DEMAGNETIZATION SENSING INPUT SECONDARY PULSES INPUT POWER TRANSISTOR CURRENT LIMITATION INPUT
IS IN I MAX
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
V CC V+ OUT
POWER SUPPLY POSITIVE OUTPUT STAGE SUPPLY POWER OUTPUT
GROUND GND GROUND GND ERROR AMPLIFIER INPUT (INVERTING) ERROR AMPLIFIER OUTPUT OVERLOAD INTEGRATION CAPACITOR E S C2
GND GROUND GND GROUND R0 C0 C1 OSCILLATOT RESISTOR OSCILLATOR CAPACITOR SOFT-START CAPACITOR
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Figure 2. Block Diagram
S
7
VCC 16
15.7V INTERNAL BIAS
V+
15
ERROR AMPLIFLIER
+
VREF 2.49V VREF (2.49V)
OVERVOLTAGE PROTECTION
7.4V
10.3V
-1
+
MODULATORS
MODULATOR LOGIC
PRIMARY PULSES
IS LOGIC
REGULATION PULSES
LOGIC PROCESSOR
AUTOMATIC BURST GENERATION REPETITIVE OVERLOAD PROTECTION
TON(Max.) (60%) SOFT-START
OSCILLATOR
2.55V
0.15V 0.6V 0.9V 10 A
SECONDARY PULSE
9
11
10
1
2
8
3
4
5
12 13
C1
R0
C0
IS IN
C2
I MAX
GND
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-
+
-
DEMAGNETIZATION SENSING
+
45 A
+
-
+
E6
-
VCC MONITORING
POSITIVE OUTPUT STAGE VCC NEGATIVE OUTPUT STAGE CURRENT LIMITATION
+ 1.2A (Max.)
14
OUT
+
- 2A (Max.)
-
-
+
TEA2261/0
SIMPLIFIED APPLICATION DIAGRAMS Figure 3. Master-Slave Concept
AUDIO OUTPUT STAGE Muting Control
R P1 Remote Stand-by
MAINS INPUT
Synchronization
SCANNING DEVICE
P2 C VOLTAGE REGULATOR Remote Stand-by V CC
TEA2260/61 SLAVE
TEA5170 MASTER
VCC
P
INFRA-RED RECEIVER PWM
P 1 : Output voltage adjustement in normal mode P 2 : Output voltage adjustement in stand-by
Power primary ground Secondary ground (isolated from mains)
Figure 4. Secondary Regulation (with optocoupler)
AUDIO OUTPUT STAGE
Muting Control
R P SCANNING DEVICE Remote Stand-by
MAINS INPUT
C VOLTAGE REGULATOR
VCC
TEA2260/61
P
VCC INFRA-RED RECEIVER
P : Output voltage adjustement
Power primary ground Secondary ground (isolated from mains)
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TEA2261/0
ABSOLUTE MAXIMUM RATINGS
Symbol VCC V+ IOUT+ IOUT Tj Tstg Parameter Power Supply V16-V4, 5, 12, 13 Output Stage Power Supply V15-V4, 5, 12, 13 Positive Output Current (source current) Negative Output Current (sink current) Operating Junction Temperature Storage Temperature Range Value 20 20 1.5 2.5 150 -40, +150 Unit V V A A oC oC
THERMAL DATA
Symbol Rth (j-c) Rth (j-a) Parameter Junction-case Thermal Resistance Junction-ambient Thermal Resistance Value 11 45 Unit
oC/W oC/W
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RECOMMENDED OPERATING CONDITIONS
Symbol VCC IOUT + IOUTIOUT + IOUTFoper VIN ROSC COSC C1 C2 C2/C1 Tamb Parameter Power Supply Positive Output Current (source current) Negative Output Current (sink current) Average Positive Output Current Average Negative Output Current Operating Frequency Input Pulses Amplitude (Pin 2) Oscillator Resistor Range Oscillator Capacitor Range Soft-starting Capacitor Range Overload Integration Capacitor Ratio C2/C1 (C2 must be C1) Operating Ambient Temperature Min. VCC stop Typ. 12 Max. VCC max 1.2 2.0 0.6 0.6 100 4.5 150 4.7 Unit V A A A A kHz V k nF F F
o
10 1.5 20 0.47 0.047 0.047 1 -20
2.5
1 1 70
C
ELECTRICAL CHARACTERISTICS (Tamb = 25oC, VCC =12V, unless otherwise specified)
Symbol Parameter POWER SUPPLY VCC(start) Starting Voltage (VCC increasing) VCC(stop) Stopping Voltage (VCC decreasing) Hyst VCC Hysteresis (VCC(start) - VCC(Stop)) ICC(start) Starting Current (VCC = 9V) Supply Current (VCC = 12V) ICC VCC(max) Overvoltage Threshold on VCC ICC(over) Supply Current after Overvoltage Detection (VCC = 17V) OSCILLATOR / PWM SECTION Delta F ----------------------F Accuracy (ROSC = 68k, COSC = 1nF) 50 Min. 9.3 6.4 2.4 Typ. 10.3 7.4 2.9 0.7 7.5 15.7 35 Max. 11.3 8.4 1.4 15 42 Unit V V V mA mA V mA
15 26
10 60 75 550 2 0.08 2.34 2.49 2.64 70
% % dB kHz mA A V
tON max Maximum Duty Cycle in Primary Regulation Mode ERROR AMPLIFIER SECTION Open Loop Gain AVO Unity Gain Frequency Fug Short Circuit Output Current (Pin 7 connected to ground) ISC E Input Bias Current (Pin 6) IBE Internal Voltage Reference (connected to error amplifier input VREF and not directly accessible) INPUT SECTION VIN IN Input Threshold (Pin 2) IS Input Threshold (Pin 1) VIS IN Input Bias Current IBIN IS Input Bias Current IBIS CURRENT LIMITATION SECTION First Current Limitation Threshold VIM1 Second Current Limitation Threshold VIM2 Thresholds Difference VIM2 - VIM1 DVIM Lock-out Threshold on Pin C2 VC2 Capacitor C2 Discharge Current IDC2 Capacitor C2 Charge Current ICC2 IBI(max) Maximum Input Bias Current (Pin 3)
0.6
0.85 0.15 0.3 0.4 600 900 300 2.55 10 45 0.2
1.2
V V A A mV mV mV V A A A
558 837 2.25
642 963 2.85
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GENERAL DESCRIPTION The TEA2260/61 is an off-line switch mode power supply controller. The synchronization function and the specific operation in stand-by mode make it well adapted to video applications such as TV sets, VCRs, monitors, etc.. The TEA2260/61 can be used in two types of architectures: - Master/Slave architecture. In this case, the TEA2260/61 drives the power transistor according to the pulse width modulated signals generated by the secondary located master circuit. A pulse transformer provides the feedback (see Figure 1). - Conventional architecture with linear feedback signal (feedback sources: optocoupler or transformer winding) (see Figure 2). Using the TEA2260/61, the stand-by auxiliary power supply, often realized with a small but costly 50Hz transformer, is no longer necessary. The burst mode operation of the TEA2260/61 makes possible the control of very low output power (down to less than 1W) with the main power transformer. When used in a master/slave architecture, the TEA2260/61 and also the power transistor turn-off can be easily synchronized with the line transformer. The switching noise cannot disturb the picture in this case. As an S.M.P.S. controller, the TEA2260/61 features the following functions: - Power supply start-up (with soft-start) - PWM generator - Direct power transistor drive (+1.2A, -2.0A) - Safety functions: pulse by pulse current limitation, output power limitation, over and under voltage lock-out. S.M.P.S. OPERATING DESCRIPTION Starting Mode - Stand By Mode Power for circuit supply is taken from the mains through a high value resistor before starting. As long as V CC of the TEA2260/61 is below VCC start, the quiescent current is very low (typically 0.7mA) and the electrolytic capacitor across V CC is linearly charged. When VCC reaches VCC start (typically 10.3V), the circuit starts, generating output pulses with a soft-starting. Then the SMPS goes into the stand-by mode and the output voltage is a percentage of the nominal output voltage (e.g. 80%). To do this, the TEA2260/61 contains all the functions required for primary mode regulation: a fixed frequency oscillator, a voltage reference, an error amplifier and a pulse width modulator (PWM). For transmission of low power with a good efficiency in stand-by, an automatic burst generation system is used, in order to avoid audible noise. Normal Mode (Secondary Regulation) The normal operating of the TV set is obtained by sending to the TEA2260/61 regulation pulses generated by a regulator located in the secondary side of the power supply. This architecture uses the "Master/Slave Concept", advantages of which are now well-known especially the very high efficiency in Stand-by mode, and the accurate regulation in Normal mode. Stand-by mode or normal mode are obtained by supplying or not the secondary regulator. This can be ordonnered for example by a microprocessor in relation with the remote control unit. Regulation pulses are applied to the TEA2260/61 through a small pulse-transformer to the IN input (Pin 2). This input is sensitive to positive square pulses. The typical threshold of this input is 0.85V. The frequency of pulses coming from the secondary regulator can be lower or higher than the frequency of the starting oscillator. The TEA2260/61 has no soft-starting system when it receives pulses from the secondary. The soft-start must be located in the secondary regulator. Due to the principle of the primary regulation, pulses generated by the starting system automatically disappear when the voltage delivered by the SMPS increases. Stand-by Mode - Normal Mode Transition During the transition there are simultaneously pulses coming from the primary and secondary regulators. These signals are not synchronized and some care has to be taken to ensure the safety of the switching power transistor. A very sure and simple way consist in checking the transformer demagnetization state. - A primary pulse is taken in account only if the transformer is demagnetized after a conduction of the power transistor required by the secondary regulator. - A secondary pulse is taken in account only if the transformer is demagnetized after a conduction of the power transistor required by the primary regulator. With this arrangement the switching safety area of the power transistor is respected and there is no risk of transformer magnetization.
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The magnetization state of the transformer is checked by sensing the voltage across a winding of the transformer (generally the same which supUndervoltage Detection. This protection works in association with the starting device "V CC switch" (see paragraph Starting-mode - stand-by mode). If VCC is lower than VCCstop (typically 7.4V) output pulses are inhibited, in order to avoid wrong operation of the power supply or bad power transistor drive. Overvoltage Detection. If VCC exceeds V CCmax (typically 15.7V) output pulses are inhibited. Restarting of the power supply is obtained by reducing VCC below VCCstop. Current Limitation of the Power Transistor. The current is measured by a shunt resistor. A double threshold system is used: - When the first threshold (VIM1) is reached, the conduction of the power transistor is stopped until the end of the period: a new conduction signal is needed to obtain conduction again. - Furthermore as long as the first threshold is reached (it means during several periods), an external capacitor C2 is charged. When the voltage plies the TEA2261). This is made by connecting a resistor between this winding and the demagnetization sensing input of the circuit (Pin 1). across the capacitor reaches VC2 (typically 2.55V) the output is inhibited. This is called the "repetitive overload protection". If the overload disappears before VC2 is reached, C2 is discharged, so transient overloads are tolerated. - Second current limitation threshold (VIM2). When this threshold is reached the output of the circuit is immediately inhibited. This protection is helpful in case of hard overload for example to avoid the magnetization of the transformer. Restart of the Power Supply. After stopping due to VC2, VIM2, V CCMax or VCCstop triggering, restart of the power supply can be obtained by the normal operating of the "VCC switch" but thanks to an integrated counter, if normal restart cannot be obtained after three trials, the circuit is definitively stopped. In this case it is necessary to reduce VCC below approximately 5V to reset the circuit. From a practical point of view, it means that the power supply has to be temporarily disconnected from any power source to get the restart.
SECURITY FUNCTIONS OF THE TEA2260 (see flowchart below)
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Figure 5. Security Flowchart (TEA2260)
S.M.P.S. starting
First threshold reached VIM1 N
Y
Y
Second threshold reached VIM2 N Pulse by pulse current limiting C 2 charged
V < 2.6V C2 VCC max reached N Normal operating C 2 discharged Restart number = 3 Y Reset C 2 discharged Y N Definitive stopping Y
Y
N S.M.P.S. stopping VCC stop reached N=N+1
N
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SECURITY FUNCTIONS OF THE TEA2261 (see flowchart below) Undervoltage Detection. This protection works in association with the starting device "V CC switch" (see paragraph Starting-mode - stand-by mode). If VCC is lower than VCCstop (typically 7.4V) output pulses are inhibited, in order to avoid wrong operation of the power supply or bad power transistor drive. Overvoltage Detection. If VCC exceeds V CCmax (typically 15.7V) output pulses are inhibited and the external capacitor C 2 is charged as long as VCC is higher than VCC stop. Restarting of the power supply is obtained by reducing VCC below VCCstop except if the voltage across C2 reaches VC2 (typically 2.55V) (refer to "Restart of the power supply" paragraph).In this last case, the circuit is definitively stopped. Current Limitation of the Power Transistor. The current is measured by a shunt resistor. A double threshold system is used: - When the first threshold (VIM1) is reached, the conduction of the power transistor is stopped until the end of the period: a new conduction signal is needed to obtain conduction again. Figure 6. Security Flowchart (TEA2260) - Furthermore as long as the first threshold is reached (it means during several periods), an external capacitor C2 is charged. When the voltage across the capacitor reaches VC2 (typically 2.55V) the output is inhibited. This is called the "repetitive overload protection". If the overload disappears before VC2 is reached, C2 is discharged, so transient overloads are tolerated. - Second current limitation threshold (VIM2). When this threshold is reached the output of the circuit is immediately inhibited. This protection is helpful in case of hard overload for example to avoid the magnetization of the transformer. Restart of the Power Supply. After stopping due to VIM2, VCCMax or V CCstop triggering, restart of the power supply can be obtained by the normal operating of the "VCC switch" VCC switch sequency from VCCstop to VCCstart. After stopping due to VC2 threshold reaching, the circuit is definitively stopped. In this case it is necessary to reduce VCC below approximately 5V to reset the circuit. From a practical point of view, it means that the power supply has to be temporarily disconnected from any power source to get the restart.
S.M.P.S. starting
First threshold reached VIM1 N
Y
Second threshold reached VIM2 Y Y C2 charged S.M.P.S. stopped
N
VCCmax reached N Normal operating C 2 discharged
Pulse by pulse current limiting C2 charged
VC2 < 2.6V VC2 < 2.6V Y N
Y
N Definitive stopping
Reset C2 discharged Y
N
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TYPICAL APPLICATION (Master/Slave Architecture)
170 VAC 270 VAC 150 F 385V 4.7k 1k 3.3 nF 22k 3W 39 2.2 /0.5W 2.2 F 16V 10 1W 330 F 25V BA157 7 1N4148 6 P2 1nF 9 19 14 BY218-100 17 22 7 6 4 5 12 13 16 15 BY218-100 21 1000 F 25V BC547C 25V 1A 1000 F 25V 10k Stand-by control 20 PLR811 12V 0.5A 470 F 25V 100 F 250V 2.2k 7.5V 1A 4 x 1N4007 3 13 BY218-600 P1 47k 120k 135V 0.8A
22k
1k
1.2nF
75 k
TEA2260/61
11 10 2 9 8 3 14 1nF 82k 330 1nF nF 330 nF 1 2.2 H
22k 2 4 6 5
47 F
BY299
SGSF 344
10 F 16V 220 16W
TEA5170
3 7 8 1 47nF
BZX85-3V0
100
330 0.135 /1W
18
2.7nF 1kV
560 pF 2% 1N4148
150pF Sync. input 6.8k
Small signal secondary ground Power primary ground Secondary ground (isolated from mains)
POUT : 140W f : 32kHz
100k 1%
TV - SET SMPS (with TEA5170)
Input voltage range Input DC voltage range Output power in normal mode Output power in stand by mode Operating frequency Efficiency at full load Efficiency in stand by mode Short circuit protected Open load protected Long duration overload protected Complete shutdown after repetitive default detection 170VAC - 270VAC 210VDC - 370VDC 25W < PO < 140W 2W < PO < 45W 32 kHz > 80% > 50%
Load Regulation (VDC = 310V)
Output 135V ( 0.18%) Output 25V ( 2%) -> (I135 : 0.01A to 0.8A ; I25 = 1A) -> (I135 : 0.8A ; I25 : 0.5A --> 1A)
Line Regulation
Output 135V ( 0.13%) Output 25V ( 0.17%) -> (210V < VDC < 370V) -> (I135 : 0.8A ; I25 : 1A)
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100pF
1k
270
TEA2261/0
PACKAGE MECHANICAL DATA 16-PINS - PLASTIC DIP Figure 7. 16-Pin Package
a1
I
b1 E
Z
b
B e3
e
D
16
9
1
8
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice.This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without the express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c)2003 STMicroelectronics - All Rights Reserved. Purchase of I2C Components by STMicroelectronics conveys a license under the Philips I2C Patent. Rights to use these components in an I2C system is granted provided that the system conforms to the I2C Standard Specification as defined by Philips. STMicroelectronics Group of Companies Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com
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