FLEXIWATT27 查看數據表（PDF） - STMicroelectronics
零件编号
产品描述 (功能)
生产厂家
FLEXIWATT27 Datasheet PDF : 17 Pages
| |||
STA530
OUTPUT BRIDGE
The Output bridge amplifier makes the single-ended to Differential conversion of the Audio signal using two
power amplifiers, one in non-inverting configuration with gain equal to 10 and the other in inverting configuration
with unity gain. To guarantee the high input impedance at the input pins, PWR_Inp1....4, the second amplifier
stages are driven by the output of the first stages respectively.
In 60W x2 channel configuration the "slave" inputs (INPUT 2/4) must be connected to GND.
POWER PROTECTION
To protect the output transistors of the power bridge a power detector is implemented (fig 1).
The current flowing in the power bridge and the voltage drop on the relevant power (Vds) are internally mea-
sured. These two parameters are converted in current and multiplied: the resulting current , Ipd, is proportional
to the instantaneous dissipated power on the relevant output transistor. The current Ipd is compared with the
reference current Ipda, if bigger (dissipated power > 18W) a current, Iprot(PD), is supplied to the Protection pin.
The aim of the current Iprot is to reduce the reference voltage for the Buck regulator supplying the power stage
of the chip, and than to reduce the dissipated power. The response time of the system must be less than
200 µSec to have an effective protection. As further protection, when Ipd reaches an higher threshold (when the
dissipated value is higher then 30W) the chip is shut down, forcing low the Stby/Mute pin, and the turn on se-
quence is restarted. The above description is relative for each channel in 4x30W configuration.
Figure 1. Power Protection Block Diagram
OUT1p
OPA
+
OUT1n
OPA
CD-1&2
ILIMP
I_pda
IPROT(ID)
+
I_pd IPROT(PD)
IPROT
TO PROT
PAD
V/I
I_Pd
x
MULTIPLIER
RSENSE
V/I
Iload
CD+1&2
D02AU1346
I_pdp
I_pd
Ilim
CURRENT
COMP.
SEQUENCE
Pdp1 TO TURN-ON/OFF
CURRENT
COMP.
SEQUENCE
Oc1 TO TURN-ON/OFF
8/17
Share Link: 