Duty ratio adjusting circuit
AssigneeNEC Corporation
InventorYoshitaka Matsuoka
Life of this patent
Estimating the term…
Abstract
A duty ratio adjusting circuit has a differential buffer (11) to produce a pulse signal (Dout) according to an input sine wave signal (Ain) and a reference voltage. The pulse signal is inverted and filtered to be supplied to a first analog buffer (14) as a direct voltage. The first analog buffer outputs voltage equal to the direct voltage. A second analog buffer (15) has the same structure as the first analog buffer and outputs voltage equal to the reference voltage. A differential amplifying circuit (16) produces an output voltage (SDout) as the reference voltage according to the difference between voltages output from the first and the second analog buffers. Capacitor (17,19) connected to lines connecting between the first and the second analog buffers and the differential amplifying circuit.
Claims7
A duty ratio adjusting circuit comprising:
- a differential buffer for producing a pulse signal according to a sine wave signal and a reference voltage;
- an inverter connected to said differential buffer for inverting the pulse signal to produce an inverted pulse signal;
- a low pass filter connected to said inverter for removing high frequency component from the inverted pulse signal to produce direct voltage;
- a first analog buffer connected to said low pass filter and having a high input impedance for producing a first buffered voltage substantially equal to the direct voltage supplied from said low pass filter;
- a second analog buffer having the same configuration as said first analog buffer for producing a second buffered voltage substantially equal to the reference voltage;
- a differential amplifying buffer connected to said first and said second buffers and said differential buffer for producing an output voltage according to the first and the second buffered voltages to supply the output voltage to said differential buffer and said second analog buffer as the reference voltage.
Dependencies are inferred from the claim text.