RP-21000 SERIES
28 VDC SOLID-STATE POWER CONTROLLERS
3B
-88 IFIED
AL
QU
DESCRIPTION
The RP-21000 Series (formerly SSP-
21110 Series) of 28 Vdc, Solid-State
Power Controllers (SSPCs) replace
electromagnetic circuit breakers and
solid-state relays rated from 2 through
25 amperes. These SSPCs offer sta-
tus outputs and permit external input
logic control so that they may be
remotely located near to the load.
There are five models in the series,
differing only in rated current, so that
fault and I
2
T trip characteristics can be
selected to protect wiring and loads.
Using Power MOSFET switches,
these Power Controllers offer low “on”
resistance, low voltage drop, high “off”
impedance, and low power dissipa-
tion. Built with Power MOSFETs and
custom monolithics and using thick-
film hybrid technology, they offer small
size, low power, and high reliability.
Built-In-Test (BIT) has been provided
to monitor, in real time, the status of
the internal circuitry as well as cir-
cuitry external to the SSPC. This BIT
monitors MOSFET failure and con-
trol circuit failure. The RP-21000
Series will operate over the full MIL
temperature range from -55°C to
+125°C with no thermal derating.
See ordering information for more
details.
FEATURES
•
Available in 2, 5, 10, 15, 20 and 25
Amp Ratings
•
True I
2
T Protection
•
Compliant to MIL-STD-704 and
MIL-H-38534
•
Isolated Control Circuitry
•
Status Outputs
•
Instant Trip Protection
•
No Thermal Derating
•
Low Power Dissipation
•
Solid-State Reliability
APPLICATIONS
Designed to replace circuit breakers
in land, air, and space vehicles, these
Solid-State Power Controllers provide
status outputs for light and heavy
overloads as well as minimum load
current.
HIGH SIDE
LOW SIDE
OR
SWITCH CONFIG.
SWITCH CONFIG.
+28 Vdc
VCC1 VCC2
POWER IN
POWER IN
PINS 6,7
+28 Vdc
VBIAS SUPPLY
INPUT
INTERNAL
POWER
SUPPLIES
VEE1
MOSFET
DRIVER,
SHORT
CIRCUIT
CONTROL,
STATUS
CIRCUIT,
AND
R
SENSE
PINS 6,7
LOAD
STATUS1
STATUS2
CONTROL
CMD
ISOLATED
CONTROL
CIRCUIT
POWER OUT
PINS 9,10
POWER OUT
PINS 9,10
LOAD
LATCHES
SLEW
CONTROL
VBIAS SUPPLY
COMMON
PIN 8
SLEW
CONTROL
PIN 8
SYSTEM
GND
FIGURE 1. RP-21000 SERIES BLOCK DIAGRAM
©
1990, 1999 Data Device Corporation
TABLE 1. ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
UNIT
Power In to Power Out
Vdc
50 continuous
100 Volts, 50 ms
transient
Power Out to Slew Control
Vdc
50 continuous
Control Input to Signal Ground
Vdc
-0.5 to VBias +0.5
Power Out to Signal Ground
Vdc
-100 to +100
VBias Voltage (see note 4)
Vdc
-0.5 to +7.0
Pin-to-Case
Vdc
-1000 to +1000
Lead Temperature (soldering)
°C
+300 (within 10 sec.)
Junction Temperature
°C
+150
TABLE 2. RECOMMENDED OPERATING CONDITIONS
PARAMETER
UNIT
VALUE
Power In to Power Out
Control Input to Signal Ground
Power Out to Signal Ground
VBias voltage (see note 4)
Vdc
Vdc
Vdc
Vdc
+9.0 to +40.0
+4.5 to VBias
-40 to +40
+4.5 to +5.5
TABLE 3. RP-21000 SPECIFICATIONS (CONTD)
PARAMETER
POWER CIRCUIT
(continued)
Output-to-Input Parasitic
Diode, Pulsed
Current Per Amp Of
Rated Current
Output-to-Input Parasitic
Diode, Forward Voltage
at Continuous Current
Isolation Resistance
Any Pin to Case
Isolation Resistance
Power Out to
Signal Ground
Voltage Drop
Trip Characteristics
Response Time
TEMPERATURE RANGE
Operating (Case)
Storage
THERMAL RESISTANCE
Case to Sink (θ
CS
)
Case to Ambient (θ
CA
)
Temperature Rise,
Junction-to-Case
PHYSICAL
CHARACTERISTICS
Size
Weight
CONDITIONS
UNIT
VALUE
Power Out Voltage >
Power In Voltage
Pulse Width
≤
100µS
Power Out Voltage >
Power In Voltage
Pin-to-Case Voltage =
100Vdc
A
4.0 typ
V
1.8 max
MΩ 50 min
Power Ground to
Signal Ground Voltage MΩ 50 min
= 50Vdc
across pins 6&7, 9&10 Vdc 0.25 max
see FIGURE 2
see FIGURE 3
°C
°C
-55 to +125
-55 to +150
TABLE 3. RP-21000 SPECIFICATIONS (SEE NOTES 1 AND 2)
PARAMETER
CONTROL CIRCUIT
Logic Type
VBias Supply Current
Control Turn-On Voltage
Control Turn-Off Voltage
Control Input Current
Control Input Current
Control Input Current
Status Output Voltage
Status Output Voltage
Status Truth Table
POWER CIRCUIT
Max. Continuous Current
"On" Resistance
Power Dissipation
Power Input Leakage
Current to Power Out
Max Load Capacitance
for Start-Up
Signal Ground to Power
Out Isolation
Output Capacitance
Trip Reset Time
Rupture Capacity
Output-to-Input Parasitic
Diode, Continuous
Current Per Amp Of
Rated Current
Unlimited
Power Out Voltage >
Power In Voltage
Power In = 9 - 40 V
(see note 2 )
Power In = 9 - 40 V
(see note 2 )
at 100 Vdc
see note 2
control voltage = 5.0 V
control voltage = 2.4 V
control voltage = 0.8 V
V
CC
= 4.5V,I
OL
=
2.5 mA
V
CC
= 4.5V,I
OH
=
-1.0mA
see TABLE 5
See TABLE 4
See TABLE 4
See TABLE 4
mA/A 0.1 max
µF/A
36 typ
pF
1000 typ
CONDITIONS
Note 3
VCC = 4.5 to 5.5 Vdc
mA
V
V
µA
µA
µA
V
V
UNIT
VALUE
TTL/CMOS
compatible
30 typ
70 max
2.0 to 5.5
-0.5 to 0.8
50 max
50 max
-50 min
0.4 max
2.4 min
°C/W 0.5
°C/W 12
Rated Load
°C
10
See FIGURE 4
g
65 max
Notes:
1. -55°C
≤
Case Temperature
≤
125°C.
2. 'A' is Amps of Rated SSPC Current.
3. Control Input must never be left floating.
4. An external 0.1µf ceramic capacitor from VBias to the +5V return ground is rec-
ommended.
TABLE 4.
PART
NUMBER
RP-21002
RP-21005
RP-21010
RP-21015
RP-21020
RP-21025
I-MAX*
(Amps)
2
5
10
15
20
25
POWER DISSIPATION
“ON”
(Watts)**
RESISTANCE
(Ohms)**
0.1
0.03
0.023
0.015
0.012
0.012
0.6
1.6
2.6
3.5
5.0
7.7
* I-MAX is the maximum continuous current.
** Specified for -55° to +105°C case temperature; Please increase by 0.6%/°C
between +105°C and +125°C Max Limit.
pF/A 300 typ
ms
A
A
30 min
Unlimited
1.0 typ
2
FUNCTIONAL DESCRIPTION
The RP-21000 series of Solid-State Power Controllers incorpo-
rate the wire protection feature of electromechanical circuit
breakers and the reliability of solid-state relays. In addition to the
solid-state relay's input logic compatibility, the RP-21000 series
provide logic compatible status outputs.
A TTL/CMOS compatible input provides external control of the
power switch's "ON/OFF" state. A logic high on this control input
turns the power to the load "on." A logic low will turn the power
switch off, which removes power from the load.
In the event of an overload the RP-21000 series will trip, just like
a circuit breaker, and automatically remove power from the load.
In order to turn back on the control input must be brought to a
logic low, and then returned to a logic high state.
As in a circuit breaker, the SSPC’s time to trip depends on the
current level. Slight overloads will cause longer trip times.
Heavy overloads will cause shorter trip times. The fault ("Instant
Trip") and I
2
T trip curve (see FIGURE 2) shows the trip time as
a function of current for a single trip or repetitive trips with at least
10 seconds between trip and turn on. Attempts to repeatedly
turn on into an overload will result in the thermal memory short-
ening each trip time. This "memory" protects the wire, load and
Solid-State Power Controller.
The status lines are TTL/CMOS compatible outputs which reflect
the state of the SSPC, the load, and the Built-In-Test (BIT) cir-
cuits. The status permits an external subsystem to monitor and
ultimately control the SSPC. TABLE 5 defines the status lines'
states which indicate the various states of the SSPC. Further
explanation of the status lines appears in the applications infor-
mation section.
The RP-21000 series SSPCs are characterized by their current
rating and maximum "on" resistance listed in TABLE 4. These
parameters are established by the number of Power FETs
placed in parallel within the SSPC.
The trip function is implemented by two separate circuits, a true
I
2
T trip comparator and a short circuit fault comparator. They are
independent of each other but work together to protect the sys-
tem.
If the load current is less than 110% of rated current, the SSPC
will never trip. If the load current is greater than 145%, the SSPC
will always trip.
For load currents less than 800%, the trip time can be found from
FIGURE 2 by drawing a horizontal line on FIGURE 2 at the cur-
rent level of interest. The SSPC will always trip at a time
between the two curves. This is true I
2
T tripping.
When the SSPC trips in accordance with the I
2
T characteristics,
the fall time is 200 µs, maximum.
For load currents greater than 1200%, the SSPC will turn off in
less than 25 µs. Between 800% and 1200%, the SSPC will turn
off in a time less than the "max. trip limit" shown in FIGURE 2
and may turn off in less than 25
µs.
When the SSPC turns off
under these fault conditions, the fall time is less than 25 µs.
10,000
INSTANT
TRIP
MAX
TRIP LIMIT
.
1,200
ALWAYS TRIP
LOAD CURRENT%I
- MAX
1,000
800
600
MIN. TRIP LIMIT
400
NEVER TRIP
200
145%
110%
0
25
µs
0.001
0.01
0.1
1.0
10
TIME
- SECONDS
FIGURE 2. TRIP CHARACTERISTICS
3
While the SSPC will always turn off in less than 25 µs when the
load current is greater than 1200%, the actual current may
"spike" to a value higher than 1200% due to circuit delays. The
MOSFETs inherently self-limit the maximum current, depending
on the number of MOSFETs and their rating.
During turn-on and turn-off the rise and fall time of the output
voltage is controlled to be less than 200 µs. This value is a com-
promise between faster response time with a greater amount of
RFI and EMI generated, and slower response time with less RFI
and EMI but greater power dissipated in the SSPC during transi-
tions. Since the Power MOSFET switches are not saturated dur-
ing transitions, the switching power dissipation is much greater
than the static dissipation, and longer transitions result in a larg-
er temperature rise. If the SSPC is rapidly turned on and off, the
high average dissipation could result in a significant temperature
rise in the SSPC. For this reason do not turn the SSPC off and
on more rapidly than 30 msec. This will limit the maximum tem-
perature of the switches to a safe level.
The RP-21000 has been designed to derive its internal power
requirements from the bias supply input (+5 Vdc).
APPLICATIONS INFORMATION
In some applications, low side switching will be required as
shown in FIGURE 1. In this configuration the load is being
switched through to system ground. The external 28 Vdc is con-
nected directly to the load while the return is connected to Pins
9 and 10, which are the Power Out pins. The Slew Control (Pin
8) is connected to maintain a controlled turn-on and turn-off of
the load current.
SELECTION
The selection of a proper sized SSPC is essential for protection
of the wire and load. This selection should be based on the
steady state and transient overload currents.
The shape of the trip curve (I
2
T) is selected as optimum to pro-
tect the system wiring. The power dissipated in the wire is the
wire resistance times the load current squared, and the temper-
ature of the wire is determined by the length of time that this
power is being dissipated. This makes the wire temperature pro-
portional to the current squared times the on time. Since the trip
curve follows this same characteristic the SSPC can accurately
predict the wire temperature rise as a result of overloads and
CONTROL INPUT
TRIP POINT
LOAD CURRENT
STATUS 2
STATUS 1
T1 T2 T3 T4 T5
T6 T7
T8 T9
T10
T11 T12
T13
SOLID-STATE POWER CONTROLLER TIMING AT 28 VDC
TIME
T1-T2
T2-3
T1-T4
T4-T5
T6-7
T7-T8
T6-T9
T10-T11
T11-T12
T11-T12
T11-T13
DESCRIPTION
TURN-ON DELAY
VOLTAGE RISE TIME
STATUS 1 & STATUS 2 TURN ON DELAY
STATUS 1 & STATUS 2 RISE AND FALL TIME
TURN OFF DELAY
VOLTAGE FALL TIME
STATUS 1 & STATUS 2 TURN OFF DELAY
TRIP TIME AFTER TURN-ON
VOLTAGE FALL TIME AFTER TRIP
VOLTAGE FALL TIME AFTER TRIP
TRIP TURN-OFF STATUS 1 DELAY
MAXIMUM
350
200
7.5
350
350
200
5.0
SEE FIG. 2
200
25
5.0
UNIT
µs
µs
ms
ns
µs
µs
ms
s
µs
µs
ms
*LOAD CURRENT < 800%
*LOAD CURRENT > 1200%
*
NOTES
*
Note: *Voltage rise/fall time is specified for Power In equal to 28 Vdc and is proportional to the Power In voltage.
FIGURE 3. SOLID-STATE POWER CONTROLLER TIMING
4
remove load current before the wiring is damaged from overtem-
perature. Of course, the wire I
2
T product should be greater than
the SSPC I
2
T product for the SSPC to protect the wire.
STATUS CODES
This section contains a fuller explanation of the conditions and
meaning of the status codes shown in TABLE 5. Each paragraph
number corresponds to the STATE in TABLE 5.
The first four conditions show the control input has commanded
the SSPC to be off:
1) The SSPC has failed or shorted to ground. STATUS 1
indicates the load is drawing current but the SSPC should be
off.
2)The SSPC has failed. STATUS 1 indicates the load is
drawing current; STATUS 2 indicates the Power MOSFET
switch is on; the SSPC should be off.
3) Normal off condition. STATUS 1 indicates the load is not
drawing current; STATUS 2 indicates the Power MOSFET
switch is off.
4) The SSPC has failed or STATUS 2 has shorted to the bias
supply. STATUS 1 indicates the load is not drawing current;
STATUS 2 indicates the Power MOSFET is on; the SSPC
should be off.
The next four conditions show the control input has commanded
the SSPC to be on:
5) The SSPC has failed or there is a short to ground on the
STATUS 2 output. STATUS 1 indicates the load is drawing
current but STATUS 2 indicates the Power MOSFET switch
is off.
6) Normal on condition. STATUS 1 indicates the load is
TABLE 5. STATUS CODES
STATE
INPUT
OUTPUT
OUTPUT
CONTROL STATUS 1
STATUS 2
(see note 1) (see note 2)
1
2
3
4
L
L
L
L
L
L
H
H
L
H
L
H
POWER
CONTROLLER
AND LOAD
STATUS
SSPC failure or
short to ground.
Load “on”; showing
SSPC failure.
Load “off”; showing
normal “off” condition.
SSPC failure or
STATUS 2 shorted
to bias supply
SSPC failure or
short to ground on
STATUS 2 line.
Load “on”; showing
normal “on” condition.
Load “off”; showing
“trip” (see note 3).
Normal power out
with load < 5% of
rated SSPC current.
PRECAUTIONS
When a short-circuit causes turn off of the SSPC, precautions
have to be taken to limit the transient voltages generated by the
wire inductance. The magnitude of this voltage is L*di/dt, where
"L" is the wire inductance in Henries and "di/dt" is the rate of
change of output current. If the SSPC turns off in 10 µsec from
a 250 amp overload (1000% for 25 amp unit) with a wire induc-
tance of only 10 µH, it would generate a spike of 125 volts. This
exceeds the voltage rating of the MOSFETs. In order to provide
protection from these transients, a transient voltage suppressor
should be used between the Power In terminal and Slew Control
(Power Ground) and a power diode should be used between the
Power Output terminals and Slew Control (Power Ground). (In
Low Side Switch Configuration, the power diode is not required).
The rating of the transient voltage suppressors should be select-
ed so that at the maximum expected short-circuit current, the
transient voltage suppressor voltage drop would not exceed the
SSPC voltage rating, and the power to be dissipated can be
safely absorbed without transient suppressor failure.
While circuit inductance can cause high voltage transients dur-
ing turn off, lack of circuit inductance can cause current tran-
sients prior to turn off. If the output of the SSPC is shorted and
there is no circuit inductance, the current from the source can
rise instantaneously to a high value. The SSPC will limit the cur-
rent to about 100 times its rating (10,000%). Circuit inductance
will limit the rate of rise of this current. The SSPC can take 25
µs to turn off. The current will always overshoot the 1200% max-
imum level of the SSPC due to this 25 µs delay. If the current
rises slowly due to circuit inductance the overshoot will be negli-
gible; if the current rises quickly the overshoot will be more sig-
nificant. In any case, the current spike will be less than 25 µs.
In most real applications there will always be significant circuit
inductance. The problem to guard against is voltage transients,
not current transients.
When testing individual SSPCs, be careful to simulate actual
system conditions.
POWER-ON RESET
When power is first applied the SSPC will be off regardless of the
CONTROL CMD input. If the CONTROL CMD input is a logic low
the SSPC is turned on by bringing the CONTROL CMD to a logic
high. If the CONTROL CMD input is at a logic high when power
is applied the SSPC may be turned on by cycling the CONTROL
CMD input to a logic low and then to a logic high. The system
controller can be programmed to do this cycling of the CON-
TROL CMD input. Subsequent loss of the bias supply power
causes the SSPC to turn off. Re-application of the bias supply
power again causes a power-on reset (refer to optional Power-on
reset.) Loss of power to the POWER IN terminals does not turn
off the SSPC and re-application of this power does not cause a
power-on reset.
5
H
L
L
6
7
8
H
H
H
L
H
H
H
L
H
Notes:
1) STATUS 1 indicates a logic low when the load is > 15% of rated SSPC current.
2) STATUS 2 indicates a logic high when the Power MOSFET switch is on.
3) Any trip condition per FIGURE 2.
5
NXP MCU
