THV3543 Datasheet, PDF (15/19 Pages) THine Electronics, Inc. – 2 channel Buck/Boost 2 channel Charge Pump Controller

THV3543_Rev.1.00_E
Switching Channel Output Voltage Mode
Output voltage mode of switching channel can be chosen the adjustable mode or the fixed mode, according to
the setting of VO1_IN pin.
When CH-1 output is connected directly to VO1_IN pin, the output voltage is turned into the fixed mode. CH-1
is fixed at 15.6V, VGH at 35.6V and VGL at -6V. When VO1_IN pin is connected to ground, the output voltage
is turned into the adjustable mode. Output voltage of CH-1, VGH and VGL can be set by an external resistance.
CH-2 is fixed at 3.3V in both modes.
Output Voltage Setting (Adjustable Mode)
In CH-1, the voltage on INV1 pin will be equal to the voltage on VREF by the action of feedback (See Figure 6). The
voltage on INV1 pin is divided Vout1 by R1 and R2.
Therefore,
Vout1×
R2
R1+ R2
=
VREF
C1
Thus,
Vout1
=
VREF
×
¹
+
R1
R2

=
1.2
×
¹
+
R1
R2

Vout1
FB1
R1
R3
R2
C2
Error AMP1
-
INV1 _{VREF +}
=1.2V
PWM
Comp.
Figure 6. CH-1 Output Voltage Setting
In VGH, the voltage on VGH_FB pin is controlled to be equal to the voltage on VREF (See Figure 7). The voltage on
INV_VGH pin is divided voltage on VGH by R4 and R5.
Therefore,
VGH
=
VREF
×
¹
+
R4
R5

=
1.2
×
¹
+
R4
R5

VGH
R4
VGH_FB
R5
COMP
-
VREF ⁺
=1.2V
Output
Circuit
Figure 7. VGH Output Voltage Setting
Copyright© 2011 THine Electronics, Inc.
15/19
THine Electronics, Inc.