CS4101 Datasheet, PDF (6/8 Pages) Cherry Semiconductor Corporation – Precision Air-Core Tach/Speedo Driver with Separate Function Generator Input

Circuit Description and Application Notes: continued
FREQ_IN
V_REG
R3
SQ_OUT
V_C(t)
+–
C_T R4
+
–
Q_SQUARE
3.4V
0.25V
CP+
Q1
2.0V
Q3 ^CP–
Q2
+
–
R_T
F/V_OUT
F to V
C4
Figure 5A: Partial Schematic of Input and Charge Pump
PW
V_CC
FREQ_IN ⁰
SQ_OUT
0
V_REG
I_CP+
V_CP+
0
T
T-PW
Figure 5B: Timing Diagram of FREQ_IN and I_CP
6