2-ch P&H injector and stepper motor driver unit

2-ch P&H injector and stepper motor driver unit. Contains two channels to drive low-impedance (P&H) injectors and stepper motor driver. Designed to drive throttle-body injectors and stepper IAC valve. It is a versatile unit.  Can be used either with SECU-3 units or with any other EMS.

Injector drivers are built on the LM1949 IC (peak/hold ratio = 4 and can’t be changed).  Current limiting in hold mode is linear, without using of PWM. Metallic enclosure used as heat sink for power dissipation. Stepper motor driver is built on the DRV8825 IC.



  • Aluminium profile metallic enclosure
  • Working voltage range – 5.5…16V
  • Voltage clamping on the outputs – 38V
  • Injector driving mode – Peak & Hold
  • Designed to drive injectors with peak-to-hold ratio = 4/1
  • By default outputs are configured for currents: peak = 4A, hold = 1А
  • Optional inversion is provided at the inputs (can be selected by corresponding PCB jumpers), as well as selection of pull-up or pull-down resistors. Thus, this unit can be driven either from Low Side, or High Side outputs of the ECU
  • Driver’s PCB has no load resistors intended for “cheating” of the ECU (not actual when using with SECU-3). If ECU outputs error (e.g. injector circuit malfunction), then it is necessary to connect 150 Ohm resistors between injector’s outputs of ECU and 12V.
  • All inputs have over voltage protection
  • All outputs have over current and over voltage protection
  • Stepper motor driver type: bipolar
  • Supported type of stepper motors: unipolar, bipolar
  • Stepper motor driver is controlled via DIR, STEP signals
  • Maximum load current of stepper motor driver is 1.5 A
  • This unit can be used either with SECU-3 units or with any other ECU/EMS.

More photos of this unit:



  1. A. Shabelnikov
    15.11.2017 @ 10:53 PM

    Обсуждение данного блока у нас на форуме http://secu-3.org/forum/viewtopic.php?f=10&t=1115

  2. A. Shabelnikov
    15.12.2017 @ 01:40 PM

    Подключение к блоку SECU-3T входов управления форсунками (на примере 1-го канала, для 2-го канала аналогично):
    Если вход подключается к выходу FE или IE, то перемычку J5 нужно разрезать, а перемучки J4, J7 соединить. R8 и VT2 выпаять. Для FE(IE) в SECU-3 Manager нужно поставить галочку инверсии. Если подключается к другому выходу (например к IGN_OUT4), то перемычки J5,J7 нужно соединить, а перемычку J4 разрезать. R8 и VT2 выпаять.

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