Method and system for implementing power reduction algorithms in a night vision system power system
View Patent ↗A night vision system comprising a power system having a low voltage unit coupled to a high voltage unit. The low voltage unit includes a low voltage controller and a low voltage table correlating step values to pulse widths, the low voltage controller obtaining a desired pulse width and accessing the table to obtain a step value. The low voltage unit transmits the step value to the high voltage unit using a pulse count modulation format. The high voltage unit includes an opto-isolator for receiving the step value from the low voltage controller and a high voltage controller demodulating the step value. In response to the step value, the high voltage controller accesses a high voltage table correlating step values to pulse width to obtain a pulse width, the high voltage controller generating a control pulse in response to the pulse width.
1. A night vision system comprising:
a power system having a low voltage unit coupled to a high voltage unit;
the low voltage unit including a low voltage controller and a low voltage table correlating step values to pulse widths, the low voltage controller obtaining a desired pulse width and accessing the table to obtain a step value;
the low voltage unit transmitting the step value to the high voltage unit using a pulse count modulation format;
the high voltage unit including an opto-isolator for receiving the step value from the low voltage controller, a high voltage controller demodulating the step value and in response to the step value accessing a high voltage table correlating step values to pulse width to obtain a pulse width, the high voltage controller generating a control pulse in response to the pulse width.
2. The night vision system of claim 1 wherein:
the pulse count modulation format includes pulses sent at a predefined frequency, with pulses inserted to represent a logic one state.
3. The night vision system of claim 1 wherein:
the high voltage controller reduces its clock speed during inactive periods.
4. The night vision system of claim 1 wherein:
the high voltage controller maintains the control pulse at a steady value when transmission from the low voltage unit to the opto isolator is interrupted.
5. The night vision system of claim 1 wherein:
the step value corresponds to pulse widths ranging from a maximum value and decreasing logarithmically to a minimum value.
6. The night vision system of claim 5 wherein:
the pulse widths decrease from the maximum value to the minimum value in decrements of 2.5%.
7. A method for controlling a night vision system, the method comprising:
in a low voltage unit, obtaining a desired pulse width and accessing a low voltage table to obtain a step value;
the low voltage unit transmitting the step value to the high voltage unit using a pulse count modulation format;
in the high voltage unit, accessing a high voltage table correlating step values to pulse width to obtain a pulse width, the high voltage unit generating a control pulse in response to the pulse width.
8. The method of claim 7 wherein:
the pulse count modulation format includes pulses sent at a predefined frequency, with pulses inserted to represent a logic one state.
9. The method of claim 7 wherein:
the high voltage controller reduces its clock speed during inactive periods.
10. The method of claim 7 wherein:
the high voltage controller maintains the control pulse at a steady value when transmission from the low voltage unit to the opto isolator is interrupted.
11. The method of claim 7 wherein:
the step value corresponds to pulse widths ranging from a maximum value and decreasing logarithmically to a minimum value.
12. The method of claim 11 wherein:
the pulse widths decrease from the maximum value to the minimum value in decrements of 2.5%.