1. Core Function & Purpose:

️· The A4935 is a *pre-driver* for three-phase MOSFET bridges. It's designed for motor control applications in automotive environments.
️· It handles the complex gate drive signals needed to efficiently switch MOSFETs.

2. Power Supplies & Regulation:

️· Dual Supplies: Requires two separate power supplies:
- VDD (Logic Supply): 3-5.5V for logic interface.
- VBB (Main Power): 7-50V for drive circuitry.
️· Gate Drive Voltage Regulation: An internal regulator maintains a gate drive voltage of approximately 13V. Below 16V, a charge pump (requiring a capacitor between CP1 and CP2) is used to maintain this voltage.
️· Bootstrap Capacitors (Cx): Needed for the high-side drivers to maintain the gate voltage when the high-side FETs are on (needed for 100% PWM).
️· Top-off Charge Pump: Maintains the high-side gate voltage when it is on, reducing the drain on the bootstrap capacitors.

3. Gate Drive Features:

️· Six High-Current Gate Drives: Designed to drive N-channel power MOSFETs.
️· Flexible Control: Accepts logic-level inputs (3.3V or 5V compatible).
️· Gate Drive Voltage Regulation: Ensures stable gate voltages even with fluctuating battery voltage.
️· Adjustable Charging/Discharging: External resistors can control the charging/discharging rate of the external FETs.

4. Control Inputs & Modes:

️· Independent PWM: Each phase can be controlled with an independent PWM signal for sinusoidal excitation.
️· Combined PWM Inputs (PWML, PWMH): Allow for simpler control schemes like high-side/low-side control or fast-decay.

5. Protection Features:

️· Undervoltage Protection: Operates within specified parameters with a VBB supply from 5.5 to 50V.
️· Overtemperature Protection: Monitors temperature and triggers a fault signal.
️· Power Bridge Fault Detection: Detects faults within the power bridge.

6. Diagnostics & Communication:

️· Fault Flag Outputs (FF1, FF2): Signal detected faults to an external controller.
️· Fault Register: An internal fault register is accessible for serial readout.

7. Key Components:

️· CP1 and CP2: Pins for the charge pump capacitor (minimum 220nF, typically 470nF).
️· Cx Pins: Connect bootstrap capacitors for high-side drivers.