| 摘要 |
Power-down mode is activated when equal voltages are detected on a pair of differential inputs. The voltage difference across the differential inputs is equalized by an equalizer and then applied to a multiplier and smoothed and filtered by a low-pass filter to produce an average signal. The average signal is compared to a reference voltage to detect when the voltage difference across the differential inputs is too small. A power-down signal is activated when the average signal is too small. The reference voltage compared can be generated by an equalizer, multiplier, and low-pass filter to match process, temperature, and supply-voltage variations in the primary signal path. The multipliers can be implemented with Gilbert cells. The equalizers can receive control signals to control attenuation of different frequency components.
|
