Abstract: An improved write drive circuit which includes a discharge circuit added to the base of the bottom transistors of the H-bridge to prevent excessive overshoot and ringing while allowing for higher data rates. The discharge circuit is turned on after the head voltage or current reaches an overshoot condition. In preferred embodiments, the discharge circuit includes variable discharge capability by selecting one or more parallel drive transistors or varying a variable delay in the discharge circuit or any combination of both variables. Both can be controlled by a word written to the disk drive pre-amp over the serial control port.

Abstract: The present invention includes a communication circuit for a head including a first row of communication points positioned along at least one edge of the communication circuit and a second row of communication points positioned along at least one edge of the communication circuit and behind the first row with the communication circuit being connected to the head through the first and second rows of connection points.

Abstract: An improved write drive circuit which provides an adjustable writer drive current and overshoot transient for a H-bridge drive circuit in a hard disk drive. The invention uses a variable capacitor circuit to give an initial boost to the write driver transistors. In a preferred embodiment, the capacitance of the variable capacitor is controlled by a word written to the disk drive pre-amp over the serial control port.

Abstract: An improved write drive circuit which provides an adjustable writer drive current and overshoot transient for a H-bridge drive circuit in a hard disk drive. The invention uses a variable capacitor circuit to give an initial boost to the write driver transistors. In a preferred embodiment, the capacitance of the variable capacitor is controlled by a word written to the disk drive pre-amp over the serial control port.

Abstract: A clamp circuit for clamping a terminal of an H-bridge circuit. The clamp circuit is capable of being applied to a voltage in excess of 5V including 8 volts.

Abstract: An active damping circuit damps the ringing effect caused by a write circuit for a disk drive. The circuit includes upper switches and lower switched current sources. A capacitive feedback is connected between the output and the lower switched current sources.

Abstract: An improved write drive circuit which reduces the ringing and overshoot transients of an H-bridge drive circuit for a hard disk drive. The invention uses a damp circuit which minimizes the amount of capacitance on the outputs of the write driver while still accomplishing the dampening of the transient ring. In a preferred embodiment, the damp circuit is a ring clamp circuit which includes a resistor connected to each node of the write head. Each resistor is then connected to the emitter of a npn transistor where the transistors have a commonly enabled gate and a common collector connected to a source voltage.