TEA2019 Просмотр технического описания (PDF) - STMicroelectronics
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TEA2019 Datasheet PDF : 7 Pages
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TEA2019
The TEA2019 has some additional capabilities
compared to the TEA2018A :
• The oscillator charge current its supplied through
an internal current generator,programmed exter-
nally - instead of using an external charging
resistor. The sawtooth so obtained is linear.
• The oscillator can be synchronized through an
internal PLL circuit. This feature provides syn-
chronization between the external sync pulse
and the end of the switching transistor current.
The sync pulse can be for example the fly-back
pulse of a TV horizontal sweep circuit. As indi-
cated in the application diagram, this pulse is
applied first to a R.C. network to obtain a low
voltage sawtooth and then to pin 7 of the circuit.
The PLL output (pin 8) supplies a correction
current to pin 9 through an external resistor, so
as to maintain the oscillator at the correct fre-
quency (refer to application note AN406/0591 for
detailed information).
• In the TEA2019, the power supply of the positive
output stage is separated from the main power
supply, so that it can be supplied from a lower
voltage in order to reduce the I.C. power dissipa-
tion.
For low power applications, the circuit can be
normally supplied by connecting pins 2 and 3
together.
• In order to protect the substrate (pin 13) from the
parasitic voltage peaks produced by negative
output current peaks at pin 14, the substrate
(pin 13) is internally separated from the negative
supply (pin 14). They must be externally con-
nected together.
• The switching transistor saturation voltage can
be monitored at pin 4. To achieve this, a high
voltage diode must be connected between the
collector of the switching transistor and pin 4.
Also a resistor must be connected from pin 4 to
V+CC (see application diagram). This arrange-
ment is useful when the chosen value of base
current is very low and as a consequence the
saturationvoltage will be high. In thisevent, when
VCE(sat) increases above 2.5V, the base current
is interrupted before the normal end of the period.
Remark : the TEA2019 can also operate without
this protection.
TYPICAL APPLICATION
4 x 1N4007
RF Filter
2 x 12mH
0.1µF
0.1µF
0.5A
Mains
Input
47µF
385V
Sync.
Pulse
82kΩ
10kΩ
1N4148 18 Ω
10µF
3.9Ω 1N4148
470µF
1.8kΩ
10kΩ
10kΩ
10Ω
47nF 7
6
5
4
3
2
C2
33nF
TEA2019
8
9
10
11
12
13
56kΩ
56kΩ
1.5nF
3.9kΩ
3.3nF 22nF
4.7Ω
120kΩ
1W
BYT
11-100
BYT11-100
3.3Ω
1
BUV
46A
n3
n0
1kΩ
3W
680Ω
3W
2.2nF
14
100Ω
0.47Ω
10µF
BYT11-800
100µF
n1 160V
120V
0.4A
BYT11-800
24V
0.5A
470µF
40V
n2
... PMAX = 60W
Free-running Frequency : 15kHz
155VRMS ≤ VAC ≤ 250VRMS
3 x 1N4001
. Outputs: 120V ± 3%, 0.4A
24V ±3%, 0.5A
. VCE Monitoring
Primary Ground
Secondary Ground
6/7
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