The Controlled Limiter is a single input, single output function. The output of the Limiter function is restricted to the range specified by the output lower and upper limits (cntl_lower and cntl_upper pins of the device).
The limit range is the value below the cntl_upper_limit and above the cntl_lower_limit at witch smoothing of the output begins (minimum positive value of voltage must exist between the cntl_upper input and the cntl_lower input at all times). For this model, then, the limit_range represents the delta with respect to the output level at witch smoothing occurs. Thus, for an input gain of 2 and output limits of 1 and -1 volts, the output will begin to smooth out at ±0.9 volts, which occurs when the input value is at ±0.4.
The Controlled Limiter tests the input values of cntl_lower and cntl_upper to make sure that they are spaced far enough apart to guarantee the existence of a linear range between them. The range is calculated as the difference between (cntl_upper - upper_delta - limit_range) and (cntl_lower + lower_delta + limit_range) and must be greater than or equal to zero.
When the limit_range is specified as a fractional value, the limit_range used in the above is taken as the calculed fraction of the difference between cntl_upper and cntl_lower. Still, the potential exists for too great a limit_range value to be specified for proper operation, in which case the model will return an error message.
This model will operate in DC, AC and Transient analysis modes.
Parameters
| Parameter | Description | Default |
|---|---|---|
| in_offset | Input offset. | 0 |
| gain | Gain. | 1 |
| upper_delta | Output upper delta. | 0 |
| lower_delta | Output lower delta. | 0 |
| limit_range | Upper and lower smoothing range. | 1.0e-6 |
| fraction | Used to control whether the limit range is specified as a fractional (TRUE) or absolute (FALSE) value. | FALSE |
Error Messages
- CLIMIT function linear range less than zero.
-
This message occurs whenever the difference between the upper and lower control input values are close enough that there is no effective room for proper limiting to occur; this indicates an error in the control input values.