SGS Thomson Microelectronics VN770P Datasheet
VN770P
QUAD SMART POWER SOLID STATE RELAY
FOR COMPLETE H BRIDGE CONFIGURATIONS
TYPE R
VN77 0P 0.270 Ω 9A 26V
* Total resistance of one side in bridge configuration
■ IDEALAS A LOWVOLTAGEBRIDGE
■ LINEARCURRENTLIMITATION
■ VERYLOW STAND-BY POWER
*I
DS(on)
OUT
V
CC
DISSIPATION
■ SHORTCIRCUIT PROTECTED
■ STATUSFLAG DIAGNOSTICS
■ OPENDRAIN DIAGNOSTICSOUTPUT
■ INTEGRATEDCLAMPING CIRCUITS
■ UNDER-VOLTAGE PROTECTION
■ ESDPROTECTION
DESCRIPTION
The VN770P is a device formed by three
monolithic chips housed in a standard SO28
package: a double high side and two low side
switches. Both the double high side and low side
switches are made using STMicroelectronics
VIPower technology. This device is suitable to
drive a DC motor in abridge configurationas well
as to be used as a quad switch for any low
voltage application. The dual high side switches
have built-in thermal shut-down to protect the
chip from over temperature and short circuit,
status output to provide indication for open load
in off and on state, overtemperature conditions
and stuck-on to V
. The low side switches are
CC
two OMNIFET types (fully autoprotected Power
MOSFET in VIPower technology). They have
built-in thermalshut-down, linearcurrent limitation
and overvoltage clamping. Fault feedback for
thermal intervention can be detected by
monitoringthe voltageat the input pin.
DUALHIGH-SIDESWITCH
From the falling edge of the input signal, the
status output, initially low to signal a fault
condition (overtemperature or open load
on-state), will go back to a high state with a
different delay in case of overtemperature (tpovl)
and in case of open open load (
) respectively.
tpol
This feature allows to discriminate the nature of
the detected fault. To protect the device against
SO-28
short circuit and over current condition, the
thermal protection turns the integrated Power
MOS off at a minimum junction temperature of
o
140
C. When this temperature returns to 125oC
the switch is automatically turned on again. In
short circuit the protection reacts with virtually no
delay, the sensor (one for each channel) being
locatedinside each of the two Power MOS areas.
This positioning allows the device to operate with
one channel in automatic thermal cycling and the
other one on a normal load. An internal function
of the devices ensures the fast demagnetization
of inductive loads with a typical voltage (V
demag
of -18V. This function allows to greatly reduces
the power dissipationaccordingto the formula:
P
dem
=0.5• L
load
• (I
load
)2• [(VCC+V
demag
)/V
demag
] • f
wheref = switching frequencyand
V
= demagnetizationvoltage.
demag
In this device if the GND pin is disconnected,with
V
not exceeding 16V, both channel will switch
CC
off.
LOW-SIDESWITCHES
During normal operation, the Input pin is
electrically connected to the gate of the internal
power MOSFET. The device then behaves like a
standard power MOSFET and can be used as a
switch from DC to 50 KHz. The only difference
from the user’s standpoint is that a small DC
current (I
) flows into the Input pin in order to
iss
supplythe internal circuitry.
)
September 1998
1/11
VN770P
BLOCK DIAGRAM
2/11
CONNECTION DIAGRAM
VN770P
PIN FUNCTION
No NAME FUNCTI O N
1, 3, 2 5 , 28 DRAI N 3 Drain of Switch 3 ( low- s id e swit ch)
2 INPUT 3 Input o f Swit ch 3 (low-side switch)
4, 11 N.C. Not Connec t ed
5, 10, 19, 24 V
6 GND Ground of Swi t ch es 1 and 2 (h igh - si de swit ches )
7 IN PUT 1 Input of S witch 1 (high-side sw it ch)
8 DIAGNOSTIC Diagnostic of Switches 1 and 2 (high-side switches)
9 IN PUT 2 Input of S witch 2 (high-side sw it ch)
12, 14, 15, 1 8 DRAIN 4 Drain of Switc h 4 (low- s id e swit ch)
13 INPUT 4 Input o f Swit ch 4 (low-side switch)
16, 17 SOURCE 4 Source of Switch 4 (low-side switch)
20, 21 SOURCE 2 Source of Switch 2 (high-side switch)
22, 23 SOURCE 1 Source of Switch 1 (high-side switch)
26, 27 SOURCE 3 Source of Switch 3 (low-side switch)
CC
Drain of Switches 1a nd 2 ( h igh-side sw itches ) an d Power Supply Voltage
3/11
VN770P
PROTECTION CIRCUITS
DUALHIGH SIDE SWITCH
The simplest way to protect the device against a
continuous reverse battery voltage (-26V) is to
insert a a smallresistor between pin 2 (GND) and
ground. The suggestedresistance value is about
150Ω. In any case the maximumvoltage drop on
this resistor should not overcome 0.5V.
If there is no need for the control unit to handle
external analog signals referred to the power
GND, the best approach is to connect the
reference potential of the control unit to the
device ground (see application circuit in fig. 3),
which becomes the common signal GND for the
whole control board avoiding shift of V
.
V
stat
ih,Vil
and
LOW SIDE SWITCHES
The devices integrate:
- OVERVOLTAGE CLAMP PROTECTION:
internally set at 42V, along with the rugged
avalanche characteristics of the Power
MOSFET stage give this device unrivalled
ruggedness and energy handling capability.
This feature is mainly important when driving
inductive loads.
- OVERTEMPERATURE AND SHORT CIRCUIT
PROTECTION: these are based on sensing
the chip temperature and are not dependent on
the input voltage. The location of the sensing
element on the chip in the power stage area
ensures fast, accurate detection of the junction
temperature. Overtemperaturecutout occurs at
minimum 150
restarted when the chip temperature falls
below 135
o
C. The device is automatically
o
C.
- STATUS FEEDBACK: In the case of an
overtemperature fault condition, a Status
Feedback is provided through the Input pin.
The internal protection circuit disconnects the
input from the gate and connects it instead to
ground via an equivalent resistance of 100 Ω.
The failure can be detected by monitoring the
voltage at the Input pin, which will be close to
ground potential.
Additional features of these devices are ESD
protection according to the Human Body model
and the ability to be driven from a TTL Logic
circuit (with a small increase inR
DS(on)
).
TRUTH TABLE (for Dual high-sideswitch only)
INP U T 1 INP UT 2 SOURC E 1 SOURCE 2 D I AGNOST IC
Normal O peration L
H
L
H
Under - voltag e X X L L H
Ther mal S h utdow n
Channel 1
Channel 2
Open Load
Channel 1
Channel 2
Out put Shorted to V
CC
Channel 1
Channel 2
NOTE: The low-side switches have the fault feedback which canbe detected by monitoring the voltage at the input pins.
L = Logic LOW, H = Logic HIGH, X = Don’t care
HXLX L
XHXL L
H
L
X
L
H
L
X
L
L
H
H
L
X
L
H
L
X
L
H
L
L
H
L
H
H
L
X
L
H
H
X
L
L
H
H
L
X
L
H
L
X
L
H
H
H
H
H
H
L
L
L
L
L
L
L
L
4/11
Loading...