Calyx S1A0071 - Audio Processor for Class-D Power AMP - Manual (Page 17)

S1A0071 Audio Processor for Class-D Power AMP
Digital & Analog Co., Ltd. (Rev. 1.0) -17-
Rp,Rn & Dead-Time
0
20
40
60
80
100
120
140
160
40 60 80 100 120 140 160 180 200 220 240
Rp&Rn (kΩ)
De
a
d
-T
im
e
[
n
S
]
Note 6
The Vc ( DC Voltage of carrier frequency) sets the oscillation level of the triangle oscillator. The
internal oscillation frequency is set to about 450kHz, independent of the oscillation level, an important
factor that sets the conversion gain from the internal comparator to the speaker. Based on the input Vc,
the oscillation level is set to approximately
± Vc (Vp-p), and can be monitored at the SIO (Pin3).
It is acceptable to make Vc voltage from the external voltage source; however, we recommend making
the Vc voltage from the regulated voltage VB (Pin22) divided by Ra and Rb. If Vc is used with the
capacitor to prevent noise input, a circuit with better characteristics can be configured.
) (
2
) (
Rb Ra
Rb VB
V VC
P P +
Ч Ч
=
−
: V
B
= 3.05V with VCC = 5V, VSS = -5V
To get the high THD characteristics, the gain of S1A0071 is designed as 26dB and the application
circuit use the ± 30V for main power and the 0.8V for Vc. The ratio of main power divide Vc relate a
amplifier gain, so if user want to get the high power and increase the main power, then user must
re-setup the Vc values. We recommended as below value for user's application.
VCCP, VSSP
± 20V ± 30V ± 45V
Ra 22K Ω 22KΩ 22KΩ
Rb 5.6K Ω 8.2KΩ 15KΩ