Mode Power Supply
Working demo boards show how
NVEs unique MSOP Isolators can shrink Switch Mode Power Supplies, increase
efficiency, and improve reliability.
In these demonstrators, Isoloop® Isolators
isolate the synchronous rectification MOSFETs and the error voltage feedback signal.
Two versions are available. SMPS1 boards use an IL610-1 failsafe isolator in the
error voltage feedback circuitry for simplicity with 1 kV of isolation.
SMPS2 uses a new IL710V-1 MSOP 2.5 kV isolator to provide a board rated at
a full 2.5 kV isolation.
Features of both demo boards are:
MSOP isolators for high density
Input voltage: 11 14 V
Output voltage: 3.3 V
Output current: 750 mA
Switching frequency: 130 kHz
Approx. one square inch boards
SMPS demo boards are in
stock for immediate delivery.
SMPS2 Demo Board (actual size)
the SMPS1 Manual >
the SMPS2 Manual >
Systems Expo & Conference (ESEC), May 13 - 15, Tokyo, Japan.
NVE sensors and isolators will be on display in cooperation with distributor KKRocky,
and there will be a live demonstration of the precision and low power of NVEs
unique AAT-Series angle sensors.
Conversion and Intelligent Motion (PCIM),
May 19 - 21, Nürnberg, Germany.
NVE Isolators will be on display at the HY-LINE Power booth and sensors will be
at the IS-LINE booth. Unique featured products will include True 8
high-voltage isolators and QSOP CAN and RS-485 isolated transceivers.
Free Registration Coupon Courtesy HY-LINE Power >
Sensor+Test 2015, May 19
- 21, Nürnberg, Germany.
NVE sensors will be on display in cooperation with distributor IS-LINE. NVE engineers
will meet customers and answer questions.
Pass Courtesy IS-LINE >
Passive-Input Isolators are popular in Programmable Logic Controllers because,
unlike other isolators, they provide channel-to-channel isolation and accommodate
a wide range of input voltage.
Typically, the Isolators are driven with a resistor in series with the input coil.
The typical minimum input current to activate the isolator is 5 mA, and the
absolute maximum DC coil current is 25 mA. This provides a 5:1 input range,
although its a bit less in practice after allowing for component tolerances,
temperature variations, etc.
But more input range is sometimes needed.
Designers have used two methods to extend the Isolators input range: a diode
in parallel with the input coil, or a Current Limiting Diode (CLD) in series.
The first method is illustrated as follows:
The 3.3 kilohm resistors ensure at least 5 mA of coil current for 20 volt
inputs. The diodes limit the coil voltages to approximately 0.7 volts, providing
22 mA coil current at the 31 ohm minimum coil resistance over the temperature
range, and 5.5 mA at the 128 ohm maximum coil resistance. Thus the coil
current is between the 5 mA maximum input threshold (with a 5 volt supply)
and the 25 mA Absolute Maximum coil current. This method allows very high
input voltages, although the drive current can be high.
Another option uses Current Limiting Diodes (CLDs):
The CLDs limit the coil currents to less than the Absolute Maximum of 25 mA,
and also limit loading of the input sources. The isolator will switch with an
input voltage as low as approximately 1 volt, and the voltage can go as high
as the CLD peak operating voltage of 45 volts. This provides more than a
40:1 input range.
Thanks to NVE customer Luis Rios for the CLD design tip!
IL600-Series Product Datasheet >