ISOVLCL-4 Regulator Board

ISOVLCL-4 Regulator Board

The ISOVLCL-4 provides the same functionality than the ISVLCL-3 board (isolated current and voltage regulation) with the enhanced functionality of potentiometer-adjustable ramp time and transistorized status signals indicating overcurrent , overvoltage, current limit, and current and voltage trip reset.

Key Features

  • Automatic crossover between regulation modes.
  • Current and Voltage Trip with Automatic Reset
  • Adjustable Soft-Start
  • Optional Proportional Plus-Integral (PI) Voltage Regulation
  • Optional Trip Latches for Voltage and Current Trips.
  • Scaled Current and Voltage Read-Back Signals.


  • Battery Chargers
  • Electro-chemical Process Power Supplies
  • Motor Controllers
  • Magnet Power Supplies
  • UPS Systems


Technical Details

The ISOVLCL-4 includes the following features:

  • Signals: The current and voltage feedback signals are galvanically isolated from the regulator board by Analog Devices AD202KN isolation amplifiers (1500 Vrms, 2000 V peak).
  • Load Voltage or Current Limit: Limit amplifiers respond to the difference between either feedback signal and the corresponding limit commands. The resulting signal is the SCR delay angle command signal, SIG HI.
  • Current and Voltage Limit Automatic Crossover: A diode OR circuit provides automatic crossover between voltage and current limiting. The ISOVLCL -4 operates in either current or voltage regulating mode depending on which limit command setting is lowest.
  • Overcurrent and Overvoltage Trip with Manual or Automatic Reset: Two board-mounted potentiometers set the current and voltage trip levels. A trip resets the soft-start circuit; its response time to an overcurrent or overvoltage event is approximately 3 milliseconds.  If this condition persists, the overcurrent or overvoltage trip will automatically reset and trip, cycling continuously until cleared.
  • Adjustable Soft-Start: The ISOVLCL-4 includes a potentiometer-adjustable soft-start ramp.
  • Polarity Reversing Compatibility: The current and voltage feedback signals are processed by precision absolute value circuits, avoiding positive feedback and permitting operation with polarity reversing applications.
  • Voltage and Current Read-Back Signals: Scaled analog voltage and current signals are available from a dedicated connector.
  • Status Interface: The ISOVLCL-4 includes an auxiliary connector with four open-collector transistors indicating the status of the overcurrent , overvoltage, manual trip, and current limit signals. Connection to common, +12 and 24 V rails are provided to drive lamps, relay coils, or other common apparatus.
  • Onboard or Offboard Voltage and Current Commands: Users may command the desired voltage or current level using board-mounted potentiometers or through externally applied voltage and current commands. Several command voltage or current ranges are available, including 0-12 V, 0-10 V, and 4-20 mA.
  • Board Construction: All circuit boards are assembled at the Enerpro plant in Goleta, California and are manufactured by a UL-approved fabricator from 2.4 mm thick FR4 fire resistant fiberglass epoxy laminate. All boards are conformal coated (MIL-1-46058, Type UR).

Enerpro applications engineers are available by e-mail or fax for applications assistance.


Enerpro, Inc.
Global Headquarters
99 Aero Camino
Goleta, CA 93117

Tel: (805) 683-2114
Fax: (805) 964-0798


ICT Power Company Inc.
1220 Corporate Dr.
Burlington, ON L7L 5R6

Tel: 905.631.8494
Fax: 905.631.8495


MPE Cathodic AS
P. O. Box 74
N1581 Rygge, Norway
Marine & Offshore
Jotun ICCP Specialists
Tel: +47 69 23 29 00
Fax: +47 69 23 29 01
Mob: +47 95 11 81 82


Andrew Chettle
Power Products International Limited
Commerce Way
Kent TN8 6ED
Tel: 01732 866424
Fax: 01732 866399


Bruno Passerini
G.P.S. – Green Power Solutions SRL
Via Venezia 34D
10088 Volpiano – Torino
Tel: +39 011 9882251
Fax: +39 011 9881358


Design Support
In-Service Support
Toll Free: (877) 648-2114
(805) 683-2114

Sales Policy
RMA Policy


Jane Lu
Tackoh Enterprises (HK)
Room 1604, Arion Commercial Centre
2-12 Queen’s Road, West
Hong Kong
Tel: 852 2543 0186
Fax: 852 2542 2114
Mob: 852 9379 8172


Andes Controls, Power and Automation
Cristián Ladisla Bohn
Av. Holanda 099, Oficina 1101
Providencia, Santiago, Chile
Tel: +56 2 2306 6202


Akom Chantakhun
CBC International Limited
56/12-13 Soi Prayasuren 45
Samwatawantok, Klongsamwa
Bangkok, 10510
Tel: 662 902 6106-9
Fax: 662 914-3009