Modification Of Antenna Short/Open Threshold; Modification Of Over Current Protection Threshold - Furuno GN-86F User Manual

3.5.3 Modification of Antenna Short/Open Threshold

The threshold currents for detecting "Antenna open" and "Antenna short" are able to be changed with
adjusting the values of resistors in Antenna Detection Circuit.
The three parameters, that are VREF_O, VREF_S and VDET, are given by following three equations.
Reference voltage for antenna open (VREF_O) is given as
Reference voltage for antenna short (VREF_S) is given as
Detection voltage (VDET) is given as
V : Transistor Q2 Collector-Emitter voltage
CE
I : Antenna current
ANT
As described in Section 3.5.2, detection conditions are as below:
Antenna open status:
Antenna short status:
Then Antenna open and short detection current are derived from above equations.
Antenna open detection current：
Antenna short detection current：
Notes: V is omitted for VANT = 5V typ. >> V
CE
So it is possible to shift the threshold current with adjusting the values of registers in above equations.

3.5.4 Modification of Over Current Protection Threshold

The setting of the Over Current Protection Threshold (I
V : Transistor Q1 Base-Emitter voltage
BE
In Figure 3-8, R2 is set to
Table 3-5.
Notes: In case of changing
resistors, inductors and capacitors.
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FURUNO GPS/GNSS Receiver 86/87 Series User's Design Guide
= 0.11V typ.
CE
5.1Ω, and VBE is 0.6V typically, so I
, please make sure the maximum current and/or the power rating of relevant
) is simple. It is given with the equation (3.6).
CC
is set to 117 mA (=0.6/5.1) as shown in
OC
18
SE13-900-001-06
(3.1)
(3.2)
(3.3)
(3.4)
(3.5)
(3.6)