8xMOSFETS-8-IN-V1_0 Hardware Schematic

Page 1: Backpanel Interface & RS485

This section details the main backpanel connector (J1), providing connections for power (+5V), communication (SDA, SCL), identification (ID0-ID2), general I/O (IO0-IO18), and control signals (PANIC, INT). It also shows the RS485 communication interface using an HS91L02W2C01 transceiver, with pins for 485A, 485B, 485-RX, 485-TX, and direction control (485-DIR). Power status indicators, including a red ERROR LED (D2) and an LEDON indicator (D35), are also present. A 3.3V voltage regulator (ME6211C33M5G-N, U3) is used.

Page 2: LED Drivers

This page illustrates the LED driver circuitry. Two 8-bit serial-in, parallel-out shift registers (74HC595PW, U4 and U5) are employed to control up to 16 LEDs. These ICs receive serial data, clock, and latch signals from the microcontroller. Each LED is connected in series with a current-limiting resistor (e.g., RN3.4 with value 1 kΩ) and a green LED (e.g., Grn D8). Capacitors (C4, C5) are used for decoupling.

Page 3: Microcontroller & System Control

The core of the system is the STM32G0B1CBT6 microcontroller (U6). It interfaces with various peripherals and external components. Key connections include:

• 8x MOSFET control signals (MOS1-MOS8)
• 8x Input signals (IN1-IN8)
• Identification signals (ID0-ID2)
• Communication interfaces: RS485 (485-TX, 485-RX), I2C (SDA, SCL)
• Debugging interface: SWD (SWDIO, SWCLK)
• Control signals: PANIC, INT, CUT

Page 4: Input Signal Isolation

This section implements 8 channels of input signal isolation using optocouplers (EL357N(B)(TA)-G, U7-U14). Each input channel (IN1-IN8) features an infrared LED within the optocoupler, driven by a resistor (e.g., R8 with value 10 kΩ) and connected to the 3.3V supply. The phototransistor output side of each optocoupler is pulled up to 3.3V via resistors (e.g., RN7.1 with value 4.7 kΩ). This provides galvanic isolation for the input signals.

Page 5: High Voltage MOSFET Drivers

This section details the high-voltage MOSFET driver circuitry. Four UCC27517DBVR driver ICs (U15-U18) are used to drive MOSFETs for high-voltage applications. Each driver controls a single MOSFET output (MOS-OUT1 to MOS-OUT4). These drivers are designed for efficient switching of N-channel MOSFETs. They are powered by a +12VV supply and include gate resistors (e.g., RN9.1 with value 1 kΩ) and decoupling capacitors (e.g., C10 with value 1 uF). The schematic also notes a "SECOND SOURCE MOSFET HSU16N25".

Page 6: High Current MOSFET Drivers

This page describes the high-current MOSFET driver stage. Similar to the previous section, four UCC27517DBVR driver ICs (U20-U23) are used to drive MOSFETs for high-current applications, controlling outputs MOS-OUT5 to MOS-OUT8. These drivers are powered by a +12VC supply. Overvoltage protection is provided by transient voltage suppressor diodes (e.g., SMAJ30A-13-F, D23-D26). This section also incorporates LTV-247 optocouplers (U24) for driving MOSFETs, along with gate resistors (e.g., RN10.1 with value 1 kΩ) and decoupling capacitors (e.g., C14 with value 1 uF).

Page 7: CRT Sensor Interface (High Voltage)

This section focuses on the Current/Voltage (CRT) sensing interface for high-voltage applications. It utilizes an ISO1540DR (U33) for signal isolation between the sensors and the microcontroller. An ADS1115IDGSR (U34) is used as a 16-bit Analog-to-Digital Converter (ADC) to digitize sensor readings. The schematic shows connections for CRT1-CRT4, SDA, SCL, and various voltage rails (VH1-VH4). Resistors (e.g., RN18.1 with value 4.7 kΩ) and capacitors (e.g., C98 with value 470 nF) are used for signal conditioning and filtering.

Page 8: CRT Sensor Interface (High Current)

Continuing the CRT sensing, this page details the high-current sensor interface. It employs INA180 (U39, U40, U41, U44) current sense amplifiers to measure current. An ADS1115IDGSR (U43) serves as the ADC for these measurements. Signal isolation is provided by an ISO1540DR (U35). Connections include SDA3, SCL3, and CRT5-CRT8 signals. The circuit uses pull-up resistors (e.g., RN20.1 with value 4.7 kΩ) and decoupling capacitors (e.g., C118 with value 470 nF).

Page 9: Power Supply

The power supply section provides the necessary voltage rails for the board. It features B0512S-1WR3 DC-DC converters (U25, U27, U29) to generate regulated voltages such as +12VC, +12VV, +5V, and +3.3V. These converters utilize inductors (e.g., L1 with value 6.8 uH) and output capacitors (e.g., C18 with value 4.7 uF) for filtering and stable voltage output. Decoupling capacitors (e.g., C19, C20, C21, C22) are used throughout the power supply circuitry.