• Four Short-circuit-protected High-side Drivers with a Maximum Current Capability of
50 mA Each
• Four Short-circuit-protected Low-side Drivers with a Maximum Current Capability of
50 mA Each
• ON Resistance High Side R
• ON Resistance Low Side R
< 10 Ω Versus Total Temperature Range
on
< 7 Ω Versus Total Temperature Range
on
• Short-circuit Detection of Each Driver Stage
• Disabling of Driver Stages in the Case of Short-circuit and Overtemperature Detection
• Independent Control of Each Driver Stage via an 8-bit Shift Register
• Status Output Reports Short-circuit Condition
• Status Output Reports when All Loads Are Switched Off
• Timing of Status Output Reset Signalizes Failure Mode
• Temperature Protection in Conjunction with Short-circuit Detection
Description
The U6820BM is a driver interface in BCDMOS technology with 8 independent driver
stages having a maximum current capability of 50 mA each. Its partitioning into 4
high-side and 4 low-side driver stages allows an easy connection of either 4 halfbridges or 2 H-bridges on the pc board. The U6820BM communicates with a microcontroller via an 8-bit serial interface. Integrated protection against short circuit and
overtemperature give added value. EMI protection and 2-kV ESD protection together
with automotive qualification referring to conducted interference (ISO/TR 7637/1)
make this IC ideal for both automotive and industrial applications.
Dual Quad
BCDMOS
Driver IC
U6820BM
Figure 1. Block Diagram
V
CC
6
V
CC
14
STATUS
HH
HH
L
S2S
S
1
4
Input Register
4
GND
CC
CLK
11
CS
12
13
DI
3SS4
HS4HS3HS2HS1
16
Current
limiter
L
L
L
S
S
S
3
2
1
V
CC
Current
limiter
Current
limiter
Control
logic
Current
limiter
9
1015
81
Current
limiter
Thermal protection
Power-on reset
Current
limiter
Current
limiter
Current
limiter
3
V
S
V
CC
V
CC
5
GND
S
27
LS1LS2LS3LS4
Rev. 4527A–BCD–03/02
1
Pin Configuration
Figure 2. Pinning SO16
HS1
LS1
VS
GNDCC
GNDS
VCC
LS2
HS2
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
HS4
LS4
STATUS
DI
CLK
CS
LS3
HS3
Pin Description
PinSymbolFunction
1HS1Output high side 1
2LS1Output low side 1
3VSSupply voltage 6 V to 18 V
4GNDCCDigital ground
5GNDSPower ground
6VCCSupply voltage 5 V (external)
7LS2Output low side 2
8HS2Output high side 2
9HS3Output high side 3
10LS3Output low side 3
11CSSet supply status (chip select)
12CLKClock line for 8-bit control shift register
13DIData line for 8-bit control shift register
14STATUSStatus output (H = fault, diagnostic “H” if all driver stages are switched off)
15LS4Output low side 4
16HS4Output high side 4
2
U6820BM
4527A–BCD–03/02
U6820BM
Description of the
Control Interface to
the Microcontroller
The serial-parallel interface basically includes an 8-bit shift register (SR), an 8-bit command register (CR) and a 4-bit counter.
The data input takes place with commands at Pins DI (data input), CS (chip select) and
CLK (clock). With a falling edge at CLK, the information at DI is transferred into the SR.
The first information written into the SR is the least significant bit (LSB). The Pin STATUS is used for diagnostic purposes and reports any fault condition to the
microcontroller.
The input CS in accordance with the CR controls the serial interface. A high level at CS
disables the SR. With a falling edge at CS, the SR is enabled. The CR control allows
only the first 8 bits to be transferred into the SR, and further clocks at CLK are ineffective. If a rising edge occurs at CS after 8 clocks precisely, the information from the SR is
transferred into the CR. If the number of clock cycles during the low phase of CS was
less or more than eight transitions, no transfer will take place. A new command switches
the output stages on or off immediately.
Each output stage is controlled by one specific bit of the CR. Low level means “supply
off” or inactive, and high level means “supply on” or active. If all 8 bits are at a low level,
the output stages will be set into standby mode.
If one of the output stages detects a short circuit and additionally overtemperature condition, the corresponding control bit in the CR is set to low. This reset has priority over
an external command to CR, thus, this does not affect the 1
tects the IC against overtemperature by activating the temperature shut down
immediately.
st
control bit. The priority pro-
The STATUS OutputThe STATUS output is at low level during normal operation. If one or more output stages
detect short circuit or if overtemperature is indicated, the STATUS output changes to
high level (OR-connection).
For diagnostic purposes (self test of the status output), the status output can also be
brought into high level during standby mode.
Timing of the Status
Output Reset Signalizes
the Failure Mode
Power-on ResetAfter switching on the supply voltage, all data latches are reset and the outputs are
The use of different reset conditions at the STATUS output simplifies the failure analysis
during normal operation, and is also beneficial during testing.
The storage content can be used for STATUS output. It is indicated and latched immediately with the rising edge of CS at STATUS output if less than 8 clocks were received
during the low phase of CS. The reset is initiated by the falling edge of the 8
(bit 7) of the next data input.
Also, the appearance of more than 8 clocks is latched and indicated at STATUS by the
rising edge of the 9
(bit 1) of the next data input.
The detection of overtemperature is latched internally. It is reset by the falling edge of
th
clock (bit 3) of a data transfer if overtemperature is no longer present.
the 4
switched off. The typical power-on reset threshold is V
vated after the first data transfer.
th
clock. The reset is initiated by the falling edge of the 2nd clock
= 3.7 V. The outputs are acti-
CC
th
clock
4527A–BCD–03/02
3
Short-circuit ProtectionThe current of the output stages is limited by an active feedback control. Short circuit at
one output stage sets the diagnostic Pin 14 (STATUS) to high. In case of both conditions, short circuit at one of the outputs and temperature detection, the affected output is
switched off selectively. It will be activated again after the first new data transfer.
Inductance ProtectionClamping diodes and FETs are integrated to protect the IC against too high or too low
voltages at the outputs. They prevent the IC from latch up and parasitic currents which
may exceed power dissipation.
Temperature ProtectionThe IC is protected by an overtemperature detection. As soon as the junction tempera-
= 155°C typically is exceeded, the diagnostic Pin 14 (STATUS) is set “high”.
ture T
j
General overtemperature detection along with short-circuit condition at a specific output
result in temperature shut down at that specific output. After temperature shut down, the
data input register has to be set again with a hysteresis of typically
=140°C).
(T
j
∆T = 15 K
ESD ProtectionAll output stages are protected against electrostatic discharge up to 5 kV (HBM) with
external components (see Figure 5), all other pins are protected up to 2 kV (HBM).
Table 1. Timing of the STATUS Output
Shift Register
0000000000000000All out = OKoffoffoffoffoffoffoffoffHNew CS
1111111111111111All on = OKononononononononL
0000000100000001E.g. one on = OKoffoffoffoffoffoffoffonL
0111111101111111Short at LS3offonononononononHNo short
1111111111101111 Temp & short at HS4onononoffononononHNew CS4
1100001100000000 V
11100011xxxxxxxxCS with less 8 CLKxxxxxxxxH New CS 8
00011100xxxxxxxx CS with more 8 CLKxxxxxxxxH New CS 2
Junction temperature rangeT
Storage temperature rangeT
1H-4H
VS
VCC
and I
j
stg
1L-4L
Thermal Resistance
ParametersSymbolValueUnit
Junction ambientR
Junction caseR
thJA
thJC
-0.3+40V
-0.3+7V
+ 0.5V
VCC
+ 0.3V
VCC
0.2mA
5mA
3065mA
-40+150°C
-55+150°C
110K/W
26K/W
Operating Range
ParametersPinSymbolValueUnit
Supply voltage3V
Logic supply voltage6V
VS
VCC
Logic input voltage low11, 12, 13CS, CLK, DI-0.2 to (0.2 x V
Logic input voltage high11, 12, 13CS, CLK, DI(0.7 x V
Logic output voltage (1 mA load)14STATUS0.5 to (V
Clock frequencyf
Junction temperature rangeT
Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty
which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any errors
which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does
not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted
by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel’s products are not authorized for use as critical
components in life support devices or systems.
Atmel® is the registered trademark of Atmel.
Other terms and product names may be the trademarks of others.
Printed on recycled paper.
4527A–BCD–03/02
xM
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