mc68hc705v12 Freescale Semiconductor, Inc, mc68hc705v12 Datasheet - Page 208

• Manufacturer Part Number: mc68hc705v12
• Description: M68hc05-based Mcu Hc05 Freescale Semiconductor
• Manufacturer: Freescale Semiconductor, Inc

Gauge Drivers
15.12.1 Minimum Voltage Operation
Advance Information
To maintain accuracy to as low a V
following equations should be used to calculate the range of values for
the external components.
V
To solve the equation, the factors involved in generating the gauge
supply voltage, V
tolerances and the tolerances of external resistors R
V
The minimum V
Where
BATT(min)
GSUP
V
SF * 12 * I
SF = % of max current driven by all coil drivers in application. Worst
case 0.707 (45
V
12 * I
V
0%.
T
R
The internal tolerances are E
I
•
•
•
Freescale Semiconductor, Inc.
Coil(max)
OL
PASS
Diode
GSUP(nom)
G1
For More Information On This Product,
R
sense resistor and is found in the electrical specifications.
I
R
Coil
= E
and R
= V
SI
Coil
Coil(max)
= Drop across reverse battery protection diode at
is the drop across the external P-channel MOSFET at
is the total of the internal resistances from the transistors and
is the minimum required coil current.
GS
GSUP(nom)
= V
is the minimum coil resistance including temperature effects.
x [R
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Coil(max)
G2
+ T
GSUP(max)
is the V
Coil(max)
GSUP
are the external resistors used to set the V
GSUP
OL(RG1)
o
Gauge Drivers
) assumes sin/cos drive algorithm.
x (1
voltage required for proper operation is given by
GSUP
, must first be calculated due to both internal
+ R
+ V
+ T
SI(max)
T
voltage generated with all tolerances set to
DIODE
OL(RG2)
OL
)
GS
]
.
+ V
BATT
and includes temperature effects.
PASS
voltage as possible, the
MC68HC705V12
G1
and R
GSUP
G2
—
voltage.
,
Rev. 3.0