M56788 Mitsubishi, M56788 Datasheet - Page 6

• Manufacturer Part Number: M56788
• Description: 5 CHANNEL ACTUATOR DRIVER
• Manufacturer: Mitsubishi

THERMAL DERATING
I/O terminal equivalent circuit
(7)CH1,CH2 power I/O terminal equivalent circuit
GND
(8)CH3,CH4,CH5 power amplifier output terminal equivalent circuit
GND
1.0
6.0
(W)
5.0
4.0
3.0
2.0
0
(VM3(+), VM3(-), VM4(+), VM4(-), VM5(+), VM5(-))
25
(VM1(+), VM1(-), VM2(+), VM2(-))
Ambient Temperature Ta(˚C)
50
75
2.6W using P-type board
3.6W using N-type board
100
125
VBS1
VBS2
Vm1
Vm2
VM
VM
150
(˚C)
The equivalent circuits of an output stage of power amplifiers are
shown in(7) and(8) .
The power supplies of CH1, CH2 are Vm1.
And the power supplies of CH3, CH4, CH5 are Vm2.
The source side of the power amplifier output stage consists of a
PNP and a NPN.
In the case of the CH1 and CH2, the emitta of the PNP is
connected to VBS1, and in the case of the CH3, CH4 and CH5, it
is connected to VBS2. So the power supplies of the PNP can be
adjusted externally.
[About bootstrap advantage]
The output stage of the power amplifier consists of the preceding
components. If VBS* is provided with higher voltage input than
Vm*(The recommendationvoltage is Vm*+1V) externally, the
output range can be wider than that of VBS*=Vm*.
Please take advantage of this bootstrap function for the system
which has many power supplies. And it is the same with the
external bootstrap circuit which provides VBS* with higher voltage
inputs than Vm*.
Also the bootstrap can decrease the saturation voltage at the
source side of the power amplifier output stage. Therefore, when
the outputs of the power amplifiers which drive motors and
actuators are fully swung, the power dissipation of the IC will be
decreased.
This IC's package is POWER-SSOP, so improving the board on
which the IC is mounted enables a large power dissipation without
a heat sink.
For example, using an 1 layer glass epoxy resin board, the IC's
power dissipation is 2.6W at least. And it comes to 3.6W by using
an improved 2 layer board.
The information of the N, P type board is shown in the board
information.
MITSUBISHI <CONTROL / DRIVER IC>
5 CHANNEL ACTUATOR DRIVER
M56788FP