ta31002a Unisonic Technologies, ta31002a Datasheet - Page 3

• Manufacturer Part Number: ta31002a
• Description: Telephone Tone Ringer
• Manufacturer: Unisonic Technologies

UTC TA31002A LINEAR INTEGRATED CIRCUIT
APPLICATION NOTE
UTCTA31002A device in typical telephone tone ringer
application.
across the TIP and RING inputs of the circuit and
is attenua-
ted by capacitor C1 and resistor R1.
on the exchanged line.
diode, the wave form is filtered by capacitor C4 to
provide a DC supply for the tone ringer chip.
oscillation starts.
chops between 512Hz (F
at a 10 Hz(F
to 8
transformer coupled loads.
the coupling C5 and transformer (1300 :8 ) are
not required.
controlled by an external resistor (R2) and capacitor
(C2).
F
at a FH1,F
and capacitor (C3). The frequency can be determined
using the relation F
1/1.203 R3*C3.
external resistor RSL, which is used to program the
slope of the supply current vs. supply voltage
characteristics (see Fig.3), and hence the supply
current up to the initiation voltage (Vsi). This initiation
voltage remains constant independent of RSL.
inversely with RSL, decreasing for increasing value
of resistance. Thus, increasing the value of RSL, will
decrease the amount of AC ringing current required to
trigger the device. As such, longer sucribser loops are
possible since less voltage is dropped per unit length of
loop wire due to the lower current level. RSL can
also be used to compensated for smaller AC coupling
capacitors (C5 on Fig.4) (higher impedance) to the
line which can be used to alter the ringer
equivalence
number of a tone ringer circuit.
current with supply voltage of the
TA31002A.
Three curves are drawn to show the variation of
initiation current with RSL. Curve B ( RSL=6.8K)
UTC
L
The application circuit illustrates the use of the
=1/1.289 R2* C2. The high frequency oscillates
After full wave rectification by the bridge
As this voltage exceeds the initiation voltage (Vsi),
With the components shown , the output frequency
When driving a pizeo-ceramic transducer type load,
Pin 2 of the UTC TA31002A allows connection of
The AC ringer signal voltage appears
C1 also provides isolation from DC voltage (48V)
The loudspeaker load is coupled through a 1300
The output coupling capacitor C5 is required with
However, a current limiting resistor is required.
The low frequency oscillator oscillates at a rate (F
The fequency can be determined using the relation
The supply current drawn prior to triggering varies
The graph in Fig.3 illustrates the variation of supply
transformer.
H2
L
) rate.
controlled by an external resistor (R3)
H1
=1/1.504 R3*C3 and F
UNISONIC TECHNOLOGIES CO., LTD.
H1
) and 640 Hz(F
UTC
H2
=
H2
)
L
)
shows the I-V characteristic for UTC TA31002A
tone ringer. Curve A is a plot with RSL<6.8K
and shows an increase in the current drawn up to the
initiation voltage Vsi. The I-V characteristic after
initiation remains unchanged. Curve C illustrates the
effect of increasing
initiation current decreases but again current
alter triggering is unchanged.
RSL above 6.8K
3