BH6511

Optical disc ICs 4-channel PWM driver for CD and MD players BH6511FS The BH6511FS is an IC designed for CD and MD player motors and actuators, and has an internal 4-channel PWM driver, and a charge pump circuit that supplies the gate drive for the output stage power MOSFET. The power MOSFET in the output stage assures low power consumption for applications. FApplications CD and MD players FFeatures 1) Internal 4-channel power MOS H-bridge. 2) Adaptable for PWM input. 3) Internal charge pump circuit to raise VG voltage. FAbsolute maximum ratings (Ta = 25_C) 4) Low ON resistance. 5) Low power consumption. 6) 32-pin SSOP-A compact package. FRecommended operating conditions 261 Optical disc ICs FBlock diagram BH6511FS FPin descriptions 262 Optical disc ICs FPin equivalent circuit diagrams BH6511FS 263 Optical disc ICs BH6511FS FElectrical characteristics (unless otherwise noted, Ta = 25_C, VM = 5V, VDD = 3V, VG = internal charge pump output, fIN = 176kHz, RL = 8Ω –47µH) 264 Optical disc ICs FMeasurement circuit BH6511FS 265 Optical disc ICs FCircuit operation (1) PWM driver The output stage is an H-bridge driver with four N-type FET circuits. Output PWM duty is changed according to input PWM duty. This pulse drives the load (direct PWM). Driver truth table BH6511FS (2) Charge pump A dedicated charge pump that supplies the drive voltage to the output stage H-bridge power MOSFET. (3) Because the charge pump circuit doubles the voltage using pin 9 voltage as its reference, VG is not output unless VM is impressed on pin 9. Also, be sure to set the VM voltage to keep the charge pump voltage under the absolute maximum rating. (4) When supplying VG directly from an external source, rather than using the internal charge pump circuit, disconnect the capacitor between pins 31 and 32. (5) A charge pump capacitor between 0.01 and 0.1µF is recommended. Using one with a greater capacity will not significantly improve performance. 266 Optical disc ICs FApplication example BH6511FS 267 Optical disc ICs FElectrical characteristic curves BH6511FS FExtermal dimensions (Units: mm) 268