Philips TEA1507 Service Manual
INTEGRATED CIRCUITS
DATA SH EET
TEA1507
GreenChipII SMPS control IC
Preliminary specification
File under Integrated Circuits, IC11
2000 Dec 05
Philips Semiconductors Preliminary specification
GreenChipII SMPS control IC TEA1507
FEATURES
Distinctive features
• Universal mains supply operation (70 to 276 V AC)
• High level of integration, giving a very low external
component count.
Green features
• Valley/zero voltage switching for minimum switching
losses
• Efficient quasi-resonant operation at high power levels
• Frequency reductionat low power standby for improved
system efficiency (<3 W)
• Burst mode operation for very low standby levels(<1 W)
• On-chip start-up current source.
handbook, halfpage
1
2
TEA1507
3
4
8
7
6
5
Protection features
• Safe restart mode for system fault conditions
• Continuous mode protection by means of
demagnetization detection (zero switch-on current)
• Accurate and adjustable overvoltage protection
• Short winding protection
• Undervoltage protection (foldback during overload)
• Overtemperature protection
• Low and adjustable overcurrent protection trip level
• Soft (re)start
• Mains voltage-dependent operation-enabling level.
APPLICATIONS
Besides typical application areas, i.e. TV and Monitor
supplies, the device can be used in all applications that
demand an efficient and cost-effective solution up to
250 W.
MGU229
Fig.1 Typical application.
2000 Dec 05 2
Philips Semiconductors Preliminary specification
GreenChipII SMPS control IC TEA1507
GENERAL DESCRIPTION
The GreenChipII is the second generation of green
Switched Mode Power Supply (SMPS) controller ICs
operatingdirectly from the rectified universalmains.A high
level of integration leads to a cost effective power supply
with a very low number of external components.
The special built-in green functions allow the efficiency to
be optimum at all power levels. This holds for
quasi-resonant operation at high power levels, as well as
fixed frequency operation with valley switching at medium
power levels. At low power (standby) levels, the system
operates at reduced frequency and with valley detection.
ORDERING INFORMATION
TYPE
NUMBER
TEA1507P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1
NAME DESCRIPTION VERSION
If burst modeoperation is applied,the standby powerlevel
can even be reduced to below 1 W.
The proprietary high voltage BCD800 process makes
direct start-up possible from the rectified mains voltage in
an effective and green way. A second low voltage
BICMOS IC is used for accurate, high speed protection
functions and control.
Highly efficient, reliable supplies can easily be designed
using the GreenChipII controller.
PACKAGE
2000 Dec 05 3
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2000 Dec 05 4
ndbook, full pagewidth
BLOCK DIAGRAM
Philips Semiconductors Preliminary specification
GreenChipII SMPS control IC TEA1507
V
CC
GND
CTRL
1
S1
2
3
2.5 V
M-level
−1
burst
detect
TEA1507
SUPPLY
MANAGEMENT
internal
FREQUENCY
UVLO start
supply
VOLTAGE
CONTROLLED
OSCILLATOR
CONTROL
OVER-
TEMPERATURE
PROTECTION
POWER-ON
RESET
MAXIMUM
ON-TIME
PROTECTION
UVLO
LOGIC
LOGIC
SQ
R
START-UP
CURRENT SOURCE
VALLEY
Q
100 mV
short
winding
OVER-
VOLTAGE
PROTECTION
DRIVER
LEB
blank
OCP
0.75 V
clamp
I
soft
start
S2
OVERPOWER
PROTECTION
8
DRAIN
HVS
7
n.c.
4
DEM
6
DRIVER
ss
0.5 V
5
I
sense
Fig.2 Block diagram.
MGU230
Philips Semiconductors Preliminary specification
GreenChipII SMPS control IC TEA1507
PINNING
SYMBOL PIN DESCRIPTION
V
CC
GND 2 ground
CTRL 3 control input
DEM 4 input from auxiliary winding for
I
sense
DRIVER 6 gate driver output
HVS 7 high voltage safety spacer, not
DRAIN 8 drain of external MOS switch, input for
1 supply voltage
demagnetization timing, OVP and OPP
5 programmable current sense input
connected
start-up current and valley sensing
handbook, halfpage
1
V
CC
2
GND
CTRL
DEM
3
4
TEA1507
MGU231
Fig.3 Pin configuration.
8
7
6
5
DRAIN
HVS
DRIVER
I
sense
FUNCTIONAL DESCRIPTION
The TEA1507 is the controller of a compact flyback
converter, with the IC situated at the primary side. An
auxiliary winding of the transformer provides
demagnetization detection and powers the IC after
start-up.
The TEA1507 operates in multi modes.
The next converter stroke is started only after
demagnetization of the transformer current (zero current
switching), while the drain voltage has reached the lowest
voltage to prevent switching losses (green function). The
primary resonant circuit of primary inductance and drain
capacitor ensures this quasi-resonant operation. The
design can be optimized in such a way that zero voltage
switching can be reached over almostthe universal mains
range.
To prevent very high frequency operation at lower loads,
the quasi-resonant operation changes smoothly in fixed
frequency PWM control.
At very low power (standby) levels, the frequency is
controlled down, via the VCO, to a minimum frequency of
about 6 kHz. Typically, 3 Watts can be achieved for a
75 W converter with an output power of 100 mW.
continue charging capacitor C
(switch S1 will be
VCC
opened), see Fig.2. The IC will activate the power
converter as soon as the voltage on pin VCC passes the
V
CC(start)
level. The IC supply is taken over by the auxiliary
windingas soon astheoutput voltage reachesitsintended
level and the IC supply from the mains voltage is
subsequently stopped for high efficiency operation (green
function).
The moment the voltage on pin VCC drops below the
V
(undervoltage lock out)level, the ICstops switching
UVLO
and enters a safe restart from the rectified mains voltage.
Inhibiting the auxiliary supply by external means causes
the converter to operate in a stable, well-defined burst
mode.
Supply management
All (internal) reference voltages are derived from a
temperature compensated, on-chip band gap circuit.
handbook, halfpage
175 kHz
f
VCO fixed quasi resonant
MGU232
Start-up, mains enabling operation level and
undervoltage lock out (see Figs. 10 and 11)
Initially, the IC is self supplying from the rectified mains
voltage via pin DRAIN. Supply capacitor C
is charged
VCC
by the internal start-up current source to a level of about
4 V or higher, depending on the drain voltage. Once the
drain voltage exceeds the M-level (mains-dependent
operation-enabling level), the start-up current source will
2000 Dec 05 5
6 kHz
power
Fig.4 Multi mode operation.
Philips Semiconductors Preliminary specification
GreenChipII SMPS control IC TEA1507
Current mode control
Current mode control is used for its good line regulation
behaviour.
The ‘on-time’ iscontrolled by theinternally inverted control
pin voltage, which is compared with the primary current
information. The primary current is sensed across an
external resistor. The driver output is latched in the logic,
preventing multiple switch-on.
The internal control voltage is inverselyproportional to the
external control pin voltage, with an offset of 1.5 V. This
means that a voltage range from 1 to 1.5 V on pin CTRL
will result in an internal control voltage range from
0.5 to 0 V(the maximum externalcontrol voltage resultsin
a minimum duty cycle).
Oscillator
The maximum fixed frequency of the oscillator isset by an
internal current source and capacitor. The maximum
frequency is reduced once the control voltage enters the
VCO control window. Then, the maximum frequency
changeslinearly with thecontrol voltage untilthe minimum
frequency is reached (see Figs 5 and 6).
Valley switching (see Fig.7)
A new cycle starts when the power switch is switched on.
After the ‘on-time’ (which is determined by the ‘sense’
voltage and the internal control voltage), the switch is
opened and the secondary stroke starts. After the
secondary stroke, the drain voltage shows an oscillation
with a frequency of approximately
where L
is the primary self inductance of the transformer
p
---------------------------------------------------2 π× L
1
×()×()
pCd
and Cd is the capacitance on the drain node.
As soon as the oscillator voltage is high again and the
secondary stroke has ended, the circuit waits for the
lowest drain voltage before starting a new primary stroke.
This method is called valley detection. Figure 7 shows the
drain voltage together with the valley signal, the signal
indicating the secondary stroke and the oscillator signal.
In an optimum design, the reflected secondary voltage on
the primary side will force the drain voltage to zero. Thus,
zero voltage switching is very possible, preventing large
1
capacitive switching losses , and
P
-- -
2
2
CV
× f××=
allowing high frequency operation, which results in small
and cost effective inductors.
Demagnetization
The system will be in discontinuous conduction mode all
the time. The oscillator will not start a new primary stroke
until the secondary stroke has ended.
Demagnetization features a cycle-by-cycle output
short-circuit protection by immediately lowering the
frequency (longer off-time), thereby reducing the power
level.
Demagnetizationrecognition is suppressedduringthe first
t
time. This suppression may be necessary in
suppr
applications where the transformer has a large leakage
inductance and at low output voltages/start-up.
Minimum and maximum ‘on-time’
The minimum ‘on-time’ of the SMPS is determined by the
Leading Edge Blanking (LEB) time. The IC limits the
‘on-time’ to 50 µs. When the system desires an ‘on-time’
longer than 50 µs, a fault condition is assumed (e.g.
removed Ci), the IC will stop switching and enter the safe
restart mode.
V
handbook, halfpage
sense(max)
Fig.5 The V
0.5 V
1 V
(typ)
sense(max)
1.5 V
(typ)
voltage as function of V
MGU233
V
CTRL
CTRL
.
2000 Dec 05 6
6 kHz
f
50 mV
(typ)
75 mV
V
(typ)
handbook, halfpage
Fig.6 The VCO frequency as function of V
MGU234
175 kHz
sense(max)
sense(max)
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