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參數(shù)資料
| 型號(hào)： | BA6820 |
| 廠商： | Rohm CO.,LTD. |
| 英文描述： | LED level meter driver, 12-point x 2 channel, VU scale, bar display |
| 中文描述： | LED電平表驅(qū)動(dòng)器，12點(diǎn)× 2通道，維旺迪規(guī)模，酒吧顯示屏 |
| 文件頁(yè)數(shù)： | 6/10頁(yè) |
| 文件大小： | 172K |
| 代理商： | BA6820 |
1
2
π
C
1
(R
IN
VR
1
)
7
32
V
CC
V
LED
V
sat
(Q
1
Q
4
)
V
DL
I
LED
667
Audio ICs
BA6820F / BA6822S / BA6822F
Attached components
C
1
and C
2
: 1
μ
F input coupling capacitors (electrolytic)
for the square-root compression amplifier. The rectified
voltage output from pins 2 and 4 is attenuated by 1.5dB
at the frequency determined by the following formula (re-
fer to the data for the relationship between the pin 2 and
4 DC voltage frequency characteristics and the LED
lighting level).
fC =
(R
IN
= input resistance)
When the LEDs light due to low-frequency mechanical
noise or induced hum, reduce the values of C
1
and C
2
to cut the cut the low-frequency frequency characteris-
tic.
VR
1
and VR
2
: 5k
to 100k
potentiometers for sen-
sitivity and L/R balance adjustment (refer to item 2 of
Circuit operation).
C
3
and C
4
: 22
μ
F electrolytic capacitors.
R
1
and R
2
: 47k
carbon-film resistors.
These resistors set the attack and release times (refer
to item 6 of the Circuit operation).
C
5
: 0.01
μ
F mylar capacitor.
R
3
: 39k
carbon-film resistor.
This resistor sets the oscillator frequency (refer to the
Operation notes).
C
6
: 100
μ
F electrolytic capacitor. This capacitor is
used as a ripple filter. The positive lead should be con-
nected close to V
CC
(pin 22), and the negative lead
close to the junction of pins 10 and 11.
Q
1
to Q
4
: 2SA854S Transistors for display switching.
If the current for one LED is I
LED
, the values of I
C
and P
C
for each of Q
1
to Q
4
when all LEDs are lit are given by:
I
C
= 6
I
LED
(for duty cycle of 7/32)
P
C
= 6
I
LED
V
sat
Choose transistors that have sufficient margin for I
C
and
P
C
.
R
4
to R
7
: 2.2k
carbon-film resistors.
These resistors limit the base current for transistors Q
1
to Q
2
. The base current is the collector current divided by
h
FE
, but as the transistors are operated in the saturation
region, h
FE
will drop considerably. Choose the resistors
so that sufficient base current flows.
LED
1
to LED
12
: SLB-26
R
8
to R
13
: 330
carbon-film resistors. These resistors
set the LED current. Four LEDs are connected to each
resistor, but as the LEDs light sequentially, only the cur-
rent for one LED flows in a resistor.
R8
13 =
V
DL
= Display switch output “L” voltage.
Circuit operation
(1)
Function
There are 12 LEDs each for the left and right channels,
and these are divided into 4 groups of six. A dynamic-
drive technique is used to drive the LEDs in order, and
provide 12 display points for each channel. A 12-point
VU-scale bar display is produced over the display range
38dB to +10dB. The top eight points have a peak hold
function which may be cancelled if required (there is no
peak hold function for DC mode).
Independent AC (two channels) and DC (one channel)
inputs are provided, and a control input pin is used to
switch between them.
In DC mode, only channel 2 operates.
A power-on mute circuit is provided, so no measures are
required to prevent erroneous lighting of the LEDs when
power is applied.
The attack and release times for the display can be set
using external components.
(2)
Input block (pins 1, 3 and 5)
Pins 1 and 3 are the AC inputs, and pin 5 is the DC input.
Pin 6 is used to switch between AC and DC input. When
the pin 6 input is “H”, AC input is selected (pins 1 and 3),
and when it is “L”, DC input (pin 5) is selected. Therefore,
if pins 1 and 3 are used for audio input, and pin 5 as the
input for signal meter output (DC) from a tuner, the switch
input (pin 6) can be used to make LED display do two
jobs.
Pins 1 and 3 have low input impedance, so we recom-
mend that you connect potentiometers (VR
1
and VR
2
:
5k
to 100k
) in series with the inputs to adjust the bal-
ance between ch1 and ch2 and set the levels.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| BA6820F | 制造商:ROHM 制造商全稱:Rohm 功能描述:LED level meter driver, 12-point x 2 channel, VU scale, bar display |
| BA6820F-E2 | 制造商:ROHM Semiconductor 功能描述:LED DRVR 5.5V 40MA 22-PIN SOP T/R - Tape and Reel 制造商:ROHM Semiconductor 功能描述:IC LED DVR 2CH 12POINT 22-SOP 制造商:ROHM Semiconductor 功能描述:LED DRVR 5.5V 40MA 22PIN |
| BA6822F | 制造商:ROHM 制造商全稱:Rohm 功能描述:LED level meter driver, 12-point x 2 channel, VU scale, bar display |
| BA6822F-E2 | 制造商:ROHM Semiconductor 功能描述:IC, 12X2 LEVEL METER DRIVER, 22 PIN SOP /TAPE & REEL - Tape and Reel 制造商:ROHM Semiconductor 功能描述:IC LED DVR 2CH 12POINT 22-SOP 制造商:ROHM Semiconductor 功能描述:IC LVL METER DRIVER 22PIN 12X2 |
| BA6822S | 制造商:Panasonic Industrial Company 功能描述:IC |
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