Toshiba Semiconductor and Storage TC78B004AFTG,EL

Overview

TC78B004AFTG from Toshiba Electronic Devices & Storage Corporation is a 3-phase full-wave sine-wave PWM brushless motor controller IC with integrated FLL+PLL speed control, built-in auto lead angle correction, and 10–28 V operation. It delivers low-noise, high-efficiency motor driving via 2-phase modulation, supports Hall sensor inputs (U/V/W ±), and provides gate drive outputs for external N-channel MOSFETs in upper/lower configurations.

For engineers reviewing the TC78B004AFTG datasheet, TC78B004AFTG pinout, TC78B004AFTG application, or TC78B004AFTG equivalent, key selection considerations include its 4–6 MHz internal reference clock dependency, 200–4000 Hz external speed command (Fref) range, 1.5 V/5 V internal regulators, open-drain READY output with ±6.25% speed tolerance, and charge pump–based high-side gate drive supporting VCC + 7.75 V.

Technical Context

The TC78B004AFTG implements a hybrid commutation strategy: it starts in 120° trapezoidal mode using Hall edge detection, then transitions to 180° sine-wave PWM when motor frequency exceeds fH (10.17–15.25 Hz, set by OSC external RC). Modulation wave generation uses real-time 60° electrical angle timing measured from Hall zero-crossings, with 32-point interpolation per phase and 1/128 PWM resolution.

Speed regulation combines FLL for coarse tracking and PLL for fine phase alignment between Fref (external clock) and FG (feedback tachometer signal); P-OUT and D-OUT provide acceleration/slowdown instructions based on cycle comparison, while gain-adjusted D-OUT amplitude scales across eight discrete voltage bands (1.0–3.5 V) depending on Fref frequency and internal counter data.

Key Specifications

Pinout & Package

Packaged in a 40-pin WQFN (P-WQFN40-0606-0.50-001), 6 mm × 6 mm, 0.5 mm pitch, exposed thermal pad. Weight: 0.0849 g (typ.).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar brushless motor controller applications.

Compared with TC78B004AFTG, STSPIN32F0B shifts control intelligence onto-die but removes direct Fref-based analog speed command simplicity, while MP6532 offloads all logic externally-making TC78B004AFTG optimal for cost-sensitive, fixed-function BLDC systems demanding plug-and-play speed regulation without MCU overhead.

Availability

TC78B004AFTG is available at Aetrix Electronics and suitable for industrial blowers, automotive HVAC fans, medical infusion pumps, and office equipment scanners requiring stable component supply, long-term production continuity, and AEC-Q100–aligned reliability.

Supply support for TC78B004AFTG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Toshiba Electronic Devices & Storage Corporation designs high-reliability semiconductor solutions for automotive, industrial, and consumer applications, with leadership in motor control, power management, and optical devices.

The TC78B004AFTG belongs to Toshiba's Bi-CMOS BLDC controller product line, engineered specifically for cost-effective, low-noise, sensor-based 3-phase motor systems where analog speed command (Fref), Hall-input compatibility, and integrated protection are mandatory.

FAQ

What is the minimum external clock (Fref) frequency supported by TC78B004AFTG before overflow occurs?

The TC78B004AFTG overflow threshold depends on the internal reference clock (fX) set via the OSC pin RC network. At fX = 4 MHz, overflow begins below ~122 Hz; at fX = 5 MHz, below ~150 Hz; and at fX = 6 MHz, below ~183 Hz. Below these frequencies, the Fref counter saturates and disables motor output. To avoid overflow, ensure Fref remains ≥200 Hz across all operating conditions - this is the guaranteed functional lower limit specified in the datasheet for TC78B004AFTG.

How does the READY output of TC78B004AFTG indicate motor speed lock status?

The READY pin on TC78B004AFTG is an open-drain output that goes Low when the measured FG feedback frequency matches the Fref command frequency within ±6.25%. Outside this window - or during standby (START = High), lock condition, or Fref overflow - READY enters high-impedance state. A pull-up resistor (typically 4.7–10 kΩ to Vreg) is required. This provides a hardware-level diagnostic flag for TC78B004AFTG speed lock status without MCU polling, simplifying system-level fault detection.

Can TC78B004AFTG drive both N-channel and P-channel high-side MOSFETs?

No, TC78B004AFTG is designed exclusively for N-channel + N-channel external power stages. Its charge pump (CP1/CP2/CP3) generates VCC + 7.75 V to drive upper Nch FET gates, and all six gate outputs (LU/LV/LW U/L) are sourced/sunk through internal resistors optimized for Nch enhancement-mode devices. Driving Pch high-side FETs would require negative gate bias or level-shifting circuitry not supported by TC78B004AFTG's architecture or pinout.

What is the purpose of the LA and L1 pins on TC78B004AFTG, and how are they used together?

The LA (Lead Angle ADC input) and L1 (external capacitor node) pins on TC78B004AFTG implement auto lead angle correction: LA accepts a voltage proportional to motor current change (dI/dt), while L1 connects to an external capacitor that sets the correction time constant. Together, they enable TC78B004AFTG to dynamically adjust commutation timing ahead of rotor position - compensating for winding inductance and maintaining optimal torque across speed and load variations. This function is active only in 180° sine-wave mode and improves efficiency by up to 8% at partial loads.

Does TC78B004AFTG require external current-sense resistors, and where are they placed?

Yes, TC78B004AFTG requires two external low-value shunt resistors for overcurrent protection. They must be placed on the low-side (GND path) of the motor phases: one between Idc1 pin and GND for phase-U current sensing, and another between Idc2 pin and GND for phase-V/W combined sensing. The IC compares these voltages against internal thresholds (e.g., 0.25 V typ. for Idc1 activation) and triggers current limiting or lock protection. No high-side or phase-leg sensing is supported - TC78B004AFTG relies solely on these two GND-referenced inputs.