TA8233BH Datasheet, PDF (3/14 Pages) Toshiba Semiconductor – 30W BTL X 2ch Audio Power Amplifier

TA8233BH
The total closed loop gain GV of this IC can be obtained by expression below when the closed loop voltage gain of
amp 1 is GV1.
GV1
=
20 log
R1+ (Rf + R2)
Rf + R2
(dB)L L L (1)
The closed loop voltage gain of power amp, amp 3 and
amp 4 is fixed at GV3≒GV4 = 20dB.
Therefore, the total closed circuit voltage gain GV is
obtained through BTL connection by the expression as
below.
GV = GV1 + GV3 + 6 (dB)………(2)
For example, when Rf = 0Ω, GV is obtained by the
expressions (1) and (2) as below.
GV≒24 + 20 + 6 = 50dB
The voltage gain is reduced when Rf is increased.
(Fig.2)
With the voltage gain reduced, since (1) the oscillation
stability is reduced, and (2) the pop noise changes
when VCC is set to on, refer to the items 3 and 4.
2. Stand-by SW function
By means of controlling pin(4) (stand-by terminal) to
high and low, the power supply can be set to on and off.
The threshold voltage of pin(4) is set at 2.1V (3VBE), and
the power supply current is about 1µA (typ.) at the
stand-by state.
Control voltage of pin(4): V (SB)
Stand-By
Power
V _(SB) (V)
On
Off
0~2
Off
On
3~V_CC
Adjustage of stand-by SW
(1) Since VCC can directly be controlled to on or off by the microcomputer, the switching relay can be omitted.
(2) Since the control current is microscopic, the switching relay of small current capacity is satisfactory for
switching
3
2002-10-30