Mosaic embedded designs » Embedded controllers » Expansion I/O modules » High current DC solid state relays

The Power I/O Wildcard™
Read switch closures and directly control high current DC devices

optically isolated open drain DC outputs
  • 8 optically isolated open-drain outputs
  • Outputs sink to 2 A continuously
  • 4 high-voltage optically isolated inputs

Do you need to interface high-voltage peripherals to your instrument? This heavy-duty board provides eight high-current outputs and four high-voltage digital inputs. Inputs and outputs are optically isolated to ±2500 volts. The Power I/O Wildcard is a versatile isolated DC solid state relays board that makes it a snap to interface high voltage peripherals to your instrumentation or automation project.

This tiny 2" by 2.5" board is a member of the Wildcard series of mezzanine boards that connect to Mosaic embedded computers and instrument controllers.

High Current Outputs

The current sinking outputs are intended to actuate high-current devices such as motors, relays, heaters and solenoids. They can each sink 2 A continuously and up to 10 A intermittently while withstanding field voltages of 50 volts, and they are snub-diode protected against kickback from inductive loads. Owing to the low ON resistance of the MOSFETs, the power dissipated in them is low: when OFF they are subjected to the field voltage but there is no current so no power is dissipated; when ON their internal resistance is low (typically 0.15 Ohm) so the I²R power is also low. The MOSFET outputs control DC loads only; to control AC loads, use the AC Relay Wildcard, also available from Mosaic Industries.

High Voltage Inputs

The opto-isolated inputs sense switch closures and/or bipolar voltages to ± 50 volts. When the input voltage is ± 5 to ± 50V, a logical one input is read. When the input voltage is less than ± 0.8V, a logical zero input is read. The high voltage inputs are also optically isolated to ± 2500 volts. Onboard pull-up resistors enable monitoring of contact closure devices such as switches.

Pre-coded Software

Precoded device drivers provide high-level functions for turning on, turning off, and toggling the output lines, for reading back the state of the outputs, and for reading the inputs.

Stepper Motor Control

Use Mosaic's tiny embedded computer, the QCard in combination with the Power I/O Wildcard for a low cost solution to stepper motor control. For detailed description of stepper motor control visit the page Controlling Stepper Motor Using the Power I/O Wildcard, or download the same page in pdf format: Application Note MI-AN-072, pdf file (249KB)


High Current DC Outputs
(each channel, without heat sink,TA= 0 to 70°C)
Output Channels: 8 isolated current sinking outputs with common field supply and ground
Isolation: Optically isolated to ±2500 V, 1011 Ohm isolation resistance
Output Protection Snub diodes to field supply to protect against inductive spikes
Field Voltage +1 to +50 VDC max
OFF Voltage +1 to +50 V (field supply)
OFF Leakage < 25 µA at 25° C
ON Voltage 0.6 V typical at 2 A continuously
0.3 V typical at 2 A intermittently
Max ON Resistance < 0.2 Ohm at I < 1A, typically 0.15 Ohm
< 0.3 Ohm to < 0.4 Ohm (at I = 2A for TA = 25 to 70°C)
Max ON Current 2 A continuously; or,
2 A pulses from 25 V at 50% duty cycle at frequencies to 5 kHz; or,
10 A pulse (< 50 msec on time, < 6% duty cycle at TA=25°C or < 4% duty cycle at TA= 70°C).
Switching Times ton = 9 µsec, toff = 12 µsec for 10%-90% transitions
Voltage / Switch Inputs
(each channel)
Input Channels: 4 isolated bipolar voltage or switch closure inputs, with a common field ground and optional pull-ups to a common field supply
Input High Voltage: ± 4 to ±50 VDC
Input Low Voltage < ±0.8 V
Switch Inputs Optionally pulled-up through 10kOhm to field supply
Isolation Optically isolated to ±2500 V, 1011 Ohm isolation resistance

Documentation and Pricing

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