| 摘要 |
<p>A write amplifier (4) comprising four current mirrors (14, 22, 30 and 38) which are turned on two at a time by two switchable floating current sources (46, 48) between the input terminals (16, 40; 24, 32) of the current mirrors in order to produce a write current of alternating polarity through the write head (2). The parasitic capacitances across the write head (2) and/or the parasitic capacitances (Cp1, Cp2) of the write amplifier (4) at the write terminals (6, 8) are compensated by means of feed-forward capacitors (170, 172, 174, 176). The high impedance at the terminals (6, 8) of the write head (2) enables the common-mode voltage across the write head (2) to be fixed at any desired voltage value by means of a common-mode circuit.</p> |
