Motor driver ICs 3-phase motor driver BA6458FP-Y The BA6458FP-Y is an one-chip IC designed for driving video cassette recorder cylinder motors. It is a high-performance IC with a 3-phase, full-wave, pseudo-linear drive system. The IC is compactly packaged. Applications Video cassette recorder cylinder motors Features 1) 3-phase, full-wave, pseudo-linear drive system. 2) Output saturation voltage is low with low variation. 3) Built-in torque limit pin. 4) Contains two amplifiers and two hysteresis amplifiers to amplify FG and PG signals. 5) Built-in thermal shutdown circuit. Block diagram 603 Motor driver ICs FAbsolute maximum ratings (Ta=25_C) FRecommended operating conditions (Ta=25_C) FPin descriptions 604 BA6458FP-Y Motor driver ICs BA6458FP-Y FElectrical characteristics (unless otherwise noted, Ta=25_C, VCC=5V, VM=12V) 605 Motor driver ICs Circuit operation (1) The 3-phase Hall signal is amplified in the hall amplifiers and sent to the matrix section, where the signal is further amplified and combined. After the signal is converted to a current in the amplitude control circuit, the current is supplied to the output driver, which then provides a motor drive current. The phases of the Hall input signal, output voltage, and output current are shown in Fig. 1. BA6458FP-Y (2) Torque control pin The output current can be controlled by adjusting the voltage applied to the torque control pin (pin 9). (3) Start / stop pin The motor is in the run mode when the pin input voltage is 3.5V or more and in the idle mode (all output transistors are off) when the voltage is 1.2V or less. (4) Power ground pin (RNF pin) The RNF pin is the output stage ground pin. Connect a resistor (0.5Ω recommended) between this pin and the ground to monitor the output current. (5) Torque limit pin (TL pin) The output current can be limited by applying a voltage to the torque limit pin. Control is provided so that this pin will have the same potential as the RNF pin. Note that there is an offset in the TL-pin voltage. (6) Phase compensation pin (CNF pin) Connect a capacitor between this pin and VCC if the output tends to oscillate. (7) Amplifiers 1 and 2 Amplifiers 1 and 2 have an open loop gain of about 70dB (typical). The input terminals are biased internally to 2.45V (typical). (8) Hysteresis amplifiers The hysteresis amplifiers have a hysteresis width of ±120mV (typical). The input terminals are biased internally. 606 Motor driver ICs Operation notes (1) Input / output circuit (1) Start / stop switching pin (25 pin) BA6458FP-Y (4) Driver output (A1: 24 pin, A2: 22 pin, A3: 21 pin) (2) Torque limit pin (18 pin) (5) Hall input (H1+: 1 pin, H1: 2 pin, H2+: 3 pin, H2: 4 pin, H3+: 5 pin, H3: 6 pin) (3) Torque control input (9 pin) (6) I / O of amplifiers 1 and 2 607 Motor driver ICs BA6458FP-Y (7) I / O of hysteresis amplifiers ∗ Note that resistance values of the I / O circuits can vary ± 30% (2) Torque control The RNF-pin output voltage is plotted against the torque control input voltage (EC) in Fig. 10. (5) Torque limit pin (pin 18) The output current can be limited by applying a voltage to the torque limit pin. Control is provided so that this pin will have the same potential as the power ground pin. Note that there is a voltage offset on this pin. The RNF-pin voltage is 0.325V when the TL-pin voltage is 0.4V (typical) and the RNF-pin resistance is 0.5Ω. Note that the voltage offset changes with the RNF-pin resistance. (6) Amplifiers 1 and 2 Unpredictable outputs may occur when the amplifier input is outside the recommended range. (3) Start / stop pin The I / O equivalent circuit of the start / stop pin is shown in (1). 1) of “Precautions for use.” The pin has a temperature dependence of *7mV / _C, and the resistance can vary ±30%. Take the temperature effect into consideration when designing your application. (4) Hall input The I / O equivalent circuit of the Hall input pins is shown in (1). 5) of “Precautions for use.” The Hall devices can be connected in either series or parallel. 608 (7) Hysteresis amplifier An input range of 0.6V to (VCC X 1.2V) is recommended. Unpredictable outputs may occur when the input is outside this range. (8) Thermal shutdown circuit (TSD) The circuit puts the driver outputs (A1, A2, and A3) to the open state at the temperature of 175_C (typical). There is a temperature difference of about 20_C between the temperatures at which the circuit is activated and deactivated. Motor driver ICs BA6458FP-Y Application example 609 Motor driver ICs Electrical characteristic curves External dimensions (Units: mm) 610 BA6458FP-Y