L9215A/G
Short-Loop Sine Wave Ringing SLIC
Data Sheet
September 2001
Supervision (continued)
Power Ring (continued)
Sine Wave Input Signal and Sine Wave Power Ring Signal Output (continued)
It is recommended that the input level at RINGIN be adjusted so that the power ring signal at tip and ring is just at
the edge or slightly clipping. This gives maximum power transfer with minimal distortion of the sine wave. The tip
side will saturate at a nominal 1 V above ground. The ring side will saturate at a nominal 3 V above battery. The
input circuit for a sine wave along with waveforms to illustrate the tip and ring saturation is shown in Figure 12.
L9215
PT
GND
+1
1 V
3 V
RINGIN
27.5x
VTIP
0.47 µF
INPUT
71 V
VRING
–1
VBAT
TR
100 kΩ
VBAT = –75 V
12-3532.H(F)
Figure 12. RINGIN Operation
The point at which clipping of the power ring signal begins at tip and ring is a function of the battery voltage, the
input capacitor at RINGIN, and the input signal at RINGIN and Vcc. Typical characteristic conditions showing the
onset of clipping are given below.
Table 21. Onset of Power Ringing Clipping VCC = 5 V, Cinput = 0.47 µF
Input
T/R
VBAT1 (V)
–70.15
–68.06
–66.00
–64.08
–62.04
–60.05
Vrms (mV)
891
Vrms (V)
46.88
45.11
Gain
52.62
52.58
52.45
52.30
52.23
52.36
858
833
43.69
42.57
41.21
39.11
814
789
747
Table 22. Onset of Power Ringing Clipping VCC = 3.1 V, Cinput = 0.47 µF
Input T/R
VBAT1 (V)
–70.12
–68.07
–66.06
–64.01
–62.00
–60.00
Vrms (mV)
894
Vrms (V)
47.15
45.11
Gain
52.74
52.76
52.65
52.5
855
824
43.38
41.95
40.79
39.09
799
780
52.29
52.19
749
Agere Systems Inc.
29
AGERE [ AGERE SYSTEMS ]
