The Supertex HV320 re-settable electronic circuit breaker is
designed to provide fast, consistent and accurate current
limiting and load isolation during fault conditions. It may be
used in a variety of applications in such markets as telecom,
power, automotive, industrial, medical and security as well
as in systems where active control is implemented in the
negative supply lead. The current trip threshold is
programmed by a sense resistor and operates from voltages
ranging from 10V to 90V differentially.
The HV320 can easily replace popular positive temperature
coefficient (PTC) products such
as Raychem™
PolySwitches™ or re-settable polyfuses. HV320 overcomes
numerous performance shortcomings of existing PTC’s,
including trip point inaccuracy, increased device resistance
after initial reset, slow response time, susceptibility to
temperature variations and very high trip current to
operating current.
During initial application of power, the gate of the external
pass device is clamped low to suppress contact bounce
glitches. Thereafter, the UV/OV supervisors and power-on
reset work together to suppress gate turn on until the input
power bounce ends. Once ON, HV320 continues to monitor
the input voltage and the load current level. If a load fault
occurs, the electronic circuit breaker will trip and the pass
element will be turned off. To restart, the UV or OV pins
must be toggled (for example by resetting the input voltage).
Applications
-48V Central Office Switching
-24V Cellular and Fixed Wireless Systems
-24V PBX Systems
Telecom Line Cards
-48V Powered Ethernet for VoIP
Distributed Power Systems
Power Supply Input/Output Fault Isolator
Electronic Circuit Breaker
Servers and SANS – replaceable modules
Automotive and Industrial Circuit Breakers
BUS Networks (CAN BUS, etc.)
Typical Application Circuit
GND
R1
487k
Vin
UV
R2
6.81k
HV320
OV
Vee
Load
Sense
R5
1k
C2
10nF
Gate
R3
C1
9.76 k
-48V
R4
5 mOhm
IRFB4710
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate
"products liability indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined
to be defective due to workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest
product specifications, refer to the Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current data book or to the
Legal/Disclaimer page on the Supertex website.
HV320
Ordering Information
Package Option
DEVICE
8 Pin SO
HV320
HV320LG
Absolute Maximum Ratings*
Vee referenced to Vin pin
V
UV
and V
OV
referenced to Vee Voltage
Operating Ambient Temperature
Operating Junction Temperature
Storage Temperature Range
+0.3V to -100V
-0.3V to +12V
-40°C to +85°C
-40°C to +125°C
-65°C to +150°C
*Absolute Maximum Ratings are those values beyond which damage to the
device may occur. Functional operation under these conditions is not
implied. Continuous operation of the devide at the absolute rating level may
affect device reliability. All voltages are referenced to device ground.
Electrical Characteristics
(-10 • V
AC Characteristics
Symbol
Parameter
EE
• -90V, -40°C • T • +85°C unless otherwise noted)
Min
Typ
Max
Units
Conditions
Supply
(Referenced to Vin Pin)
Vee
Iee
Supply Voltage
Supply Current
pin)
1.26
1.16
100
1.0
1.26
1.16
100
1.0
V
V
mV
nA
V
V
mV
nA
V
OV
= V
EE
+ 0.5V @ 25° C
Vuv = V
EE
+ 1.9V @ 25° C
Low to High Transition
High to Low Transition
Low to High Transition
High to Low Transition
-90
400
-10
450
V
µA
V
EE
= -48V
OV and UV Control
(Referenced to V
V
UVH
V
UVL
V
UVHY
I
UV
V
OVH
V
OVL
V
OVHY
I
OV
UV High Threshold
UV Low Threshold
UV Hysteresis
UV Input Current
OV High Threshold
OV Low Threshold
OV Hysteresis
OV Input Current
EE
Circuit Breaker
(V
V
SENSE-CB
t
CBTRIP
I
SENSE-CB
UV
= V
EE
+ 1.9V, V
OV
= V
EE
+ 0.5V, External MOSFET is IRFFR120N)
80
2.0
100
120
5.0
1.0
mV
µs
nA
Referenced to V
EE
pin @ 25°
C
May be extended by
external RC circuit
V
SENSE-CB
= 100mV @ 25° C
Circuit Breaker Threshold Voltage
Circuit Breaker Delay Time
IRFB4710 and IRFFR120 are registered trademarks of International Rectifier.
Raychem and PolySwitch are registered trademarks of Tyco International.
2
HV320
Gate Drive Output
(Referenced to V
V
GATE
I
GATEUP
I
GATEDOWN
V
GATELOW
Gate Drive Pull-Up Current
EE
pin, External MOSFET is IRFB4710*)
8.5
500
40
400
10
12
V
µA
mA
mV
V
UV
= Vee +1.9V,
V
OV
= Vee +0.5V
V
UV
= Vee +1.9V,
V
OV
= Vee +0.5V
V
UV
= Vee,
V
OV
= Vee +0.5V
V
UV
= Vee,
V
OV
= Vee +0.5V, Igate = 5mA
Maximum Gate Drive Voltage
Gate Drive Pull-Down Current
Minimum Gate Drive Voltage
Dynamic Characteristics
(See timing below, External MOSFET is IRFB4710)
t
GATEHLOV
t
GATEHLUV
OV High to GATE Low
UV Low to GATE Low
500
500
ns
ns
Pulsed V
OV
from V
EE
+0.5V to V
EE
+1.9V
Pulsed V
UV
from V
EE
+1.9V to V
EE
+0.5V
V
UV
Vuvl
t
GATEHLUV
V
OV
Vgate
Vovh
t
GATEHLOV
Vgate
Pinout for LG
Top View
NC
OV
UV
Vee
1
2
3
4
8
7
6
5
Vin
NC
Gate
Sense
Pin Description
OV --
This Over Voltage (OV) sense pin, when raised above its high threshold limit, will immediately cause the GATE pin to be
-
pulled low. The GATE pin will remain low until the voltage on this pin falls below the low threshold limit, initiating a new start-up
cycle.
UV
– This Under Voltage (UV) sense pin, when below its low threshold limit, will immediately cause the GATE pin to be pulled
low. The GATE pin will remain low until the voltage on this pin rises above the high threshold limit, initiating a new start-up
cycle.
V
EE
– This pin is the negative terminal of the power supply input to the circuit.
-
V
IN
--
This pin is the positive terminal of the power supply input to the circuit.
GATE --
This is the Gate Driver Output for the external N-Channel MOSFET.
-
SENSE --
The current sense resistor connected from this pin to the V
EE
Pin programs the circuit breaker trip threshold.
-
3
HV320
Functional Block Diagram
UV
Regulator
& POR
-
+
Vin
Vbg
Logic
UVLO
buffer
-
OV
Gate
+
100mV
Vee
+
-
Sense
Functional Description
HV320 as a fuse and circuit breaker replacement:
Telecom, data networks, automotive, industrial controls
and some computer applications require the ability to
isolate the power source from a load fault without having
to physically replace a fuse or manually reset a
mechanical circuit breaker. Traditionally a fast acting fuse
or Positive Temperature Coefficient (PTC) device such as
Raychem’s
PolySwitch or a manual / thermal circuit
breaker have been used to limit the fault current.
The problems with PTCs are numerous. First, they are
extremely temperature dependent. For example the
required trip current can vary as high as 150% of nominal
value at lower temperatures such as –40°C and as low as
50% of nominal value at higher temperatures such as
+85°C.
Second, the ratio of trip current to steady state current can
range from 7 to 70. This implies for an application where
steady state current is 4A, traces must be over designed
to withstand the trip current of 100A, a ratio of 25:1. Third,
PTC’s once tripped, require 20 seconds to minutes to
reset and even when they are reset, the resistance value
can permanently change as much as 240%. This implies
PTC’s are not suitable for repeated short circuit
applications. Lastly the surface mount PTCs typically have
large end cap terminations that absorb heat during the
reflow process and can result in insufficient solder and
cold solder joints. It is not uncommon for PCB surface
contaminations to be present, thus resulting in poor
solderability, hence loss of yield.
Typically, fuses are rated in Amp^2-seconds. For a SMT
1206 size fast-acting 2A, 63V fuse rated at 0.23 A - square
4
second, it could take more than 200A for 5µs before the
fusing element melts.
HV320 is an ideal alternative to thermal and manual circuit
breakers in DC input applications. It has wide variety of
uses in the automotive industry, such as PCB trace /
device protection and DC motors and solenoid actuator
current limit protection. These devices are typically used in
windows and seat adjustment operations as well as
automatic trunk opening mechanisms. Since these
devices are operated manually, they can remain energized
by the operator even after the mechanical lever has
reached its end of travel. In this case, back EMF that
normally opposes the supply voltage will drop to zero and
a large current surge can begin to flow. HV320 can
accurately be programmed to trip the current. In industrial
applications, HV320 can offer broad solutions in DC
solenoid-operated valves, DC motors and other
electromagnetic loads.
Fault current magnitude can be scaled to different current
ratings by proper selection of the sense resistor and the
external N-Channel MOSFET. For higher current
applications, IGBT devices may be considered. The
HV320 is intended to provide this circuit breaker function
on supply rails in the range of
−10
to
−90
Volts.
Description of Operation
During initial application of power, a unique proprietary
circuit holds off the external MOSFET, preventing an input
glitch while an internal regulator establishes an internal
operating voltage of approximately 10V. Until the proper
internal voltage is achieved, all circuits are held reset and
the gate to source voltage of the external MOSFET is
clamped low. Once the internal under voltage lock out
HV320
(UVLO) has been satisfied, the circuit checks the input
supply under voltage (UV) and over voltage (OV) sense
circuits to ensure that the input voltage is within
programmed limits. These limits are determined by the
selected values of resistors R1, R2 and R3 that form a
voltage divider. Once the input voltage is within the
programmed limits, the controller will force the GATE
terminal to nominal 10V and the circuit breaker supervisor
is enabled.
When the voltage on the SENSE pin rises to 100mV,
indicating an over current condition, the circuit breaker will
trip in less than 5
µ
s. This time may be extended by the
addition of external components (refer to Application
Circuit 3 on page 9). The gate voltage is latched off when
an over current condition is detected and is reset by
removal and reapplication of input power.
At any time during the start up cycle or thereafter, crossing
the UV and OV limits (including hysteresis) will cause an
immediate reset of all internal circuitry. When the input
supply voltage returns to a value within the programmed
UV and OV limits, a new start up sequence will be
initiated.
Safety recommendation:
For safety critical applications
where UL, CSA or other safety agency approvals are
required, a fuse must be placed in series with HV320.
Although HV320 will protect a fuse from opening in many
instances, from the safety agency point of view, ICs
For healthcare professionals, accurate diagnosis and treatment are crucial for a clear picture of a person's health. However, healthcare professionals often rely on tests at medical facilities, cli...[详细]
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