Non-Linear Current IDAC With Synthesis In Time Domain

摘要

An electrical current (“I”) digital-to-analog converter (“IDAC”) (60) supplies a specified electrical current to at least one light emitting diode. The IDAC (60) a plurality of current sources/sinks (26):
a. that are connected in parallel so a total amount of current flowing through the at least one LED equals the sum of their individual electrical currents; andb. at any instant in time individual current sources/sinks (26) are either:
1. turned on: or2. turned off.

When the specified electrical current being supplied exceeds a pre-established threshold (94), a sequence of individual current sources/sinks (26) are turned on ever more quickly to produce a non-linearly increasing electrical current. When the specified electrical current being supplied is below the pre-established current threshold (94), the nonlinearly increasing electrical current is supplied by an increasing number of additional current sources/sinks (26), each additional current source/sink producing progressively longer current pulses until that current source/sink (26) remains fully on.

主权项

1. A method for supplying a specified electrical current to at least one light emitting diode (“LED”) included in a display from a current (“I”) digital-to-analog converter (“IDAC”) (60), the IDAC (60) including a plurality of individual current sources/sinks (26):
a. for connecting in parallel to the LED so that a total amount of electrical current flowing through the LED equals the sum of individual electrical currents respectively flowing through each of the current sources/sinks (26); and b. at any instant in time connected current sources/sinks (26) being either:
i. turned on for supplying electrical current to the LED: orii. turned off thereby supplying no electrical current to the LED,the method for supplying the specified electrical current comprising the steps of:
a. when the specified electrical current exceeds a pre-established current threshold (94), increasing the electrical current flowing through the LED is effected by successively turning on individual current sources/sinks (26) included in the IDAC (60) that had been previously turned off; and b. when the specified electrical current is less that the pre-established current threshold (94), increasing the electrical current flowing through the LED is effected by turning on at least one additional current source/sink (26) included in the IDAC (60) that had been previously turned off, the additional current source/sink (26) being alternatively initially turned on and then subsequently turned off so as to thereby generate a sequence of progressively longer electrical current pulses (102) until the additional current source/sink (26) remains fully on.