COMPLETE PURE SINE WAVE BOARD

It’s a double-layer board with separate control and power driver sections, created in Proteus by our company Casino Digital Tech.

Let’s break down every part of this design step by step 👇

1. Overall Layout Overview

This board combines:

• Control Stage (upper section) — handles logic, PWM generation, voltage sensing, feedback, and LCD/keypad interface.

• Driver & Power Stage (lower section) — drives MOSFETs/IGBTs in the H-bridge inverter stage and manages high current switching.

You can see the board clearly divided horizontally:

• 🔹 Top half = Control & Low voltage.

• 🔹 Bottom half = Power Driver (Gate drivers, capacitors, and H-bridge interface).

2. Control Section (Top Half)

a. Microcontroller & Timing

• Dspic30f2010 socket (U1 area)
  Generates SPWM (Sine Pulse Width Modulation) signals for inverter operation.

• Crystal (6.144 MHz) — precise timing for SPWM generation.

• Reset and decoupling network around MCU ensures stability.

b. Display and Interface

• LCD Connector (labeled LCD) — connects to a 16x2 or 20x4 LCD to display voltage, frequency, mode, etc.

• KEYPAD Connector — for user settings (mode select, up/down, set).

c. Sensing Inputs

• Battery Sensor — voltage divider networks labeled:

  47K for 12V
  100K for 24V
  220K for 48V
  

  Used for scaling battery voltage to ADC input range (0–5V).

• Current Sensor Input — uses LM393 comparator and shunt resistor to monitor load current.

• AC Voltage Feedback — voltage sense from inverter output via resistor divider → rectified → LM393/LM358 comparator for RMS monitoring.

• Temperature Sensor — nearby NTC input (marked “Thermistor”) to detect transformer or MOSFET heat.

d. Power Regulation

• 7805 Regulator (U5/U6) — generates +5V for control logic and sensors.

• Filter capacitors (10µF/50V, 104, 470µF/50V) ensure clean DC for MCU.

e. Protection & Buzzer

• BUZ — alarm buzzer, triggered on fault (low battery, overload, etc.).

• 1N4148 diodes — used for signal isolation and protection.

• Relay section (12V Relay) near AC-IN — controls bypass or charger relay.

3. Driver Section (Middle Zone)

a. Gate Driver Stage

• TLP250 ICs (Optocoupler Driver ICs) — isolate and drive the high-side and low-side MOSFETs.

  • Each TLP250 drives a pair of MOSFETs (one high-side, one low-side) in the H-bridge.

  • Four TLP250s indicate a full-bridge inverter topology.

• BD139 transistor — pre-driver or gate booster for MOSFETs.

• Resistors (4.7Ω, 10Ω) — gate resistors controlling switching speed.

• 1N4148 diodes — feedback diodes to discharge gate charge quickly during switching.

b. Gate Supply and Decoupling

• 18V Gate Drive Supply — used for powering TLP250 drivers (seen near +18V labels).

• 100nF (104) and 470µF capacitors — decouple gate driver power for stability.

4. Power Output Section (Bottom Half)

a. H-Bridge MOSFET/IGBT Section

• L1, L2, H1, H2 — large pads for MOSFETs/IGBTs (mounted on heatsink).

  • Likely four or eight power switches depending on capacity.

  • Connected in full-bridge topology for AC output generation.

• 4700µF/50V capacitors — used for DC bus filtering to smooth battery voltage before inversion.

• Thick red traces — high current DC bus lines.

• Blue traces — ground return path.

b. Output and Transformer Interface

• N-IN / N-OUT terminals — connection points to transformer primary windings.

• AC-IN/OUT terminals — grid and output connections for charging or bypass.

• Relay (12V) — used for automatic changeover (switch between inverter and grid supply).

5. Additional Components

• LM393 — dual comparator for current and voltage feedback.

• TLP250 section filtering — ensures clean PWM drive.

• 1N5408/1N4007 diodes — power path protection and flyback suppression.

6. System Operation Summary

 Modes:

1. Inverter Mode:

   • Microcontroller generates SPWM.

   • TLP250 drivers switch MOSFETs alternately to create AC at the transformer output.

   • Feedback ensures stable 230V AC output.

2. Charging / Bypass Mode:

   • Relay connects AC-IN to battery and output.

   • MCU monitors battery voltage via the divider and cuts off when full.

3. Protection Features:

   • Overload: sensed by LM393 comparator and shuts down inverter.

   • Low Battery: buzzer alert and inverter cutoff.

   • Overheat: thermistor detection stops inverter.

   • Short Circuit: immediate relay release.

7. Design Credit

Printed label shows:

CASINO DIGITAL TECH ENGINEERING SERVICES
Smart Pure Sine Wave Inverter – 500W–3500W
PCB designed by your team.

That matches your company’s known inverter line.

8. Key Features Identified

Feature	Component
MCU control	DSPIC30F2010
SPWM generation	Firmware on MCU
Gate drive isolation	TLP250
Power switching	MOSFET/IGBT bank
Current feedback	LM393 + shunt
Battery sensing	Resistor network
LCD Display	LCD connector
User input	Keypad port
Protections	Overload, Overheat, Low Batt
Output	230V AC pure sine
Capacity range	500W – 3500W

Contact: +2348146005581