Preliminary Data Sheet
September 2001
L9216B/H
High-Voltage Ringing SLIC with Ground Start
During nonring modes, the PWM waveform may be left
on at RING
IN
. Via the state table, the ring signal will be
removed from tip and ring even if the low-voltage input
is still present at RING
IN
. There are certain timing con-
siderations that should be made with respect to state
changes which are detailed in the
Switching Behavior
of L9215/6 Ringing SLIC
Application Note.
Square Wave Input Signal and Trapezoidal Power
Ring Signal Output
A low-voltage square wave signal may be used to pro-
vide the ringing input to RING
IN
. The signal is applied
through a low-pass filter and ac-coupled into RING
IN
as
shown in Figure 12 and Table 23. This approach gives
a trapezoidal wave output at tip and ring.
Using this approach, a trapezoidal waveform can be
achieved at tip and ring. This has the advantage of
increasing the power transfer to the load for a given
battery voltage, thus increasing the effective ringing
loop length as compared to a sine wave. The actual
crest factor achieved is a function of the magnitude of
the battery, the magnitude of the input voltage, fre-
quency, and R
1
.
Supervision
(continued)
Power Ring
(continued)
3.3 V V
CC
Operation
A PWM signal was generated with an
HP
8116 Func-
tion Generator modulated with a 20 Hz signal. The opti-
mal frequency used was 10 kHz. The PWM signal
amplitude was 3.10 V (0 V to 3.10 V). This input signal
is shown in Figure 16.
12-3571F
Figure 16. 3.3 V PWM Signal Amplitude
This produced 44.96 Vrms ringing signal on tip/ring
under open-loop conditions and 42.0 Vrms was deliv-
ered to 5 REN load. The ringing output on ring with V
CC
= 3.1 V is shown in Figure 17.
CH1
CH2
CH3
CH4
1660
12-3572F
Notes:
The modulating 20 Hz signal THD was measured at 1.3%.
The tip/ring 20 Hz signal THD was measured at 1%.
V
BAT1
= –70.6 V, V
BAT2
= –26.5 V, V
CC
= 3.10 V.
PWM input 10 kHz, 3.1 Vp-p.
R
1
= 10 kΩ, C
1
= 0.22
µF,
C
2
= 0.47
µF.
Notes:
CH1—CMOS Input (5 V) at RING
IN
.
CH2—Filtered input at RING
IN
.
CH3—Tip.
CH4—Ring.
R
1
= 14 kΩ, C
1
= 1.0
µF,
C
2
= 0.47
µF.
V
BAT1
= –70 V, Vrms = 51 V, V
p-p
= 67 V, frequency = 20 Hz, Crest
Factor = 1.3.
Figure 17. Ringing Output on RING, with V
CC
= 3.1 V
Figure 18. Square Wave Input Signal and Trapezoi-
dal Power Ring Signal Output
Agere Systems Inc.
29
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
