TC78S121FTG TOSHIBA CD Process Integrated Circuit Silicon Monolithic TC78S121FTG PWM Chopper Type Dual-Stepping Motor Driver The TC78S121FTG is a PWM chopper type dual-stepping motor driver. Two stepping motor drivers can drive up to four brushed DC motors. Incorporating two pairs of H-bridge drivers, the TC78S121FTG can drive two DC motors or a single stepping motor. Features QFN48-P-0707-0.50 Single-chip motor driver for bipolar stepping motor Weight: 0.137 (g) control Monolithic IC structured by CD process. Low ON-resistance: R = 0.6 on In large mode, ON-resistance of combined H-bridges is (R ) is 0.3 on Over-current detection (ISD), thermal shutdown (TSD) and V power-on reset circuits M Since the IC incorporates the V regulator for internal circuit operation, an external power supply (5 V) CC is not required. Package: QFN48-P-0707-0.50 Maximum output withstand voltage: 40 V (max) Output current: 2.0 A (max) in DC Motor (S) mode 1.5 A (max) in Stepping Motor (S) mode Chopping frequency can be set by external capacitor and resistor. High-speed chopping is possible at 100 kHz or higher. 2016-2017 1 2017-09-15 Toshiba Electronic Devices & Storage Corporation TC78S121FTG Block Diagram (Stepping Motor (S) 2-ch Control Mode) PHASE X SLEEP VMR Detect IN X1 VCC VCC Voltage IN X2 Step Decoder Regulator MODE0 (Input Logic) MODE1 MODE2 Chopper OSC D TBLANK OSCM ALERT OSC Current Level Set VREF X 2bit D/A Torque Control (Angle Control) CR-CLK Converter Current Feedback (2) VM VRS1 RS COMP1 RS A RS B Output Control VRS2 RS COMP2 (Mixed Decay Control) RS C RS D ISD TSD Output Output (H-Bridge 2) (H-Bridge 2) VMR Detect VM Detection Circuit Stepping Stepping Motor Motor *: means the ellipsis of A / B / C / D of each Ch. (PHASE X, IN X1/X2, and VREF X) Note: GND wiring: We recommend that a heat sink be grounded at all points, and the board be grounded at only one GND pin for single point ground. Take the heat dissipation into consideration when designing the board. When in controlling the setting pins for each mode by SW, those pins should be pulled up to power supply like V or pulled down to GND not to go into a high-impedance (Hi-Z) state. CC Utmost care is necessary in the design of the output line, V line and GND line since IC may be M destroyed due to short-circuit between outputs, to supply, or to ground. Especially for those pins that are connected to power supply and get a large current flow (such as V , M RS, OUT and GND), they should be properly wired otherwise troubles including destruction may occur to this IC. If the logic input pins are not wired properly, malfunction that would destroy the IC may occur due to a large current exceeding the absolute maximum ratings. Care should be taken in the design of board layouts and implementation of the IC. 2 2017-09-15