HPW7095 Datasheet, PDF (17/23 Pages) List of Unclassifed Manufacturers – 6-Channel DC/DC Converter Control IC

HPW7095/A
Function Descriptions (Cont.)
Output Switch Control Circuit
The output switch control circuit outputs a signal to
control external p-channel MOSFETs for preventing
reactive current flow to external step-up circuits on
CH5 and CH6. When a “H” level
signal is applied to SWIN pin after releasing the UVLO
and the voltage at CIN6 pin rises above 0.9V(typical),
the IC pulls low the voltage at SWOUT pin, turning on
the external p-channel MOSFETs to generate output
voltages.
Application Information
Output Voltage Settings
The output voltage is set by the external resistor-di-
vider connected with converter output, error amplifier
input, and ground.
(1) CH1 to CH3, CH5
Vo
(V)
=
1.25V
⋅
1+

R1
R2


VO
R1
IN1
Error
Amp. 1
R2
1.25 V
Soft-Start Interval Settings
The CH6 soft-start time depends on the capacitor CCIN6
and is determined as the following equation:
ts(S)=- ^{CCIN6(F)⋅37.5(kΩ)⋅62.5(kΩ)} ⋅ln1− ^VCIN6(V)
100(kΩ)
 ^1.26(V) 
V CIN6
CIN6
VB(2V)
37.5k
Error
Amp. 6
(2) CH4
Vo (V) = - 1.25V ⋅ ^R1
R2
VO
R1
ts (S) ≈ 1.25 ⋅ C^INS^A4(9µ0F0)000
fOSC (kHz) ≈
R2 _{ORUTTA4(k Ω) ⋅ CT (pF)}
R3
I N4
INV
Amp. 4
Error
Amp. 4
CC I N 6
62.5k
The soft-start time until CH6 output voltage reaches
95% of the set voltage is determined as the following
equation:
ts (S) ≈ 0.07 ⋅ CCIN6 ( µF)
On CH1 to CH5, the soft-start time depending on the
capacitor CS determined as the following equation :
Triangular Oscillator Frequency Setting
The triangular oscillator frequency set by the timing
capacitor (CT) connected to the CT pin and the timing
resistor (RT) connected to the RT pin determined as
the following equation:
1.2 5V
(3) CH6
Vo (V) = 1.26V ⋅ 1+ ^R1 
 R2 
VO
R1
IN6
R2
CIN6
VB(2V)
37.5k
62.5k
Error
Amp. 6
Time Constant Setting for Timer-Latch Short-Cir-
cuit Protection Circuit
The time constant for timer-latch short-circuit protec-
tion is set by the capacitor CSCP and determined as
the following equation :
tPE (S) = 0.70 ⋅ CSCP ( µF)
 Copyright HIPAC Semiconductor, Inc.
17
Rev. A.2 - July., 2004
www.hipacsemi.com