access icon free Low-power buffer with voltage boosting and improved frequency compensation for liquid crystal display source drivers

A pair of complementary class-A buffers with voltage boosting method and improved frequency compensation is proposed. The buffer driving capabilities are enhanced by adding small auxiliary transistors to pull-up/pull-down the gate voltages of the buffer output transistors to improve the transient response. The auxiliary transistors are turned off for power saving in the steady-state operation. The proposed frequency compensation is more area-efficient than the Miller compensation method and hence maintains the high output voltage slew rate of the buffer. The measured static current of each buffer with the proposed circuits consumes 3 μA under a supply voltage of 5 V. The buffer settling times of the rising and the falling edges with a capacitance of 600 pF for an input swing of 5 V are 3.3 and 1.7 μs, respectively. The core size of the buffers including the compensation capacitance is 82 × 101 µm2 and the buffer can be stable when a load capacitance changes from 5 to 600 PF. Hence, the proposed output buffers concurrently achieve a fast response and are suitable for a wide range of load capacitances.

Inspec keywords: transient response; compensation; liquid crystal displays; low-power electronics; driver circuits; buffer circuits

Other keywords: time 3.3 mus; low-power buffer; high output voltage slew rate; complementary class-A buffers; transient response; capacitance 5 pF to 600 pF; voltage 5 V; time 1.7 mus; current 3 muA; small auxiliary transistors; Miller compensation method; steady-state operation; voltage boosting method; liquid crystal display source drivers; frequency compensation; load capacitances

Subjects: Power electronics, supply and supervisory circuits; Liquid crystal devices

References

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http://iet.metastore.ingenta.com/content/journals/10.1049/iet-cds.2013.0334
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