ISL78229 Datasheet, PDF (53/71 Pages) Intersil Corporation – 2-Phase Boost Controller with Drivers

ISL78229
READ_VOUT (89h)
Definition: This command returns output voltage reading with value of the FB pin voltage.
The READ_VIN command has two data bytes formatted as 16Lu (refer to “Read the 16Lu Data to Report the 10-Bit ADC Input Voltage” on
page 42), where the Bits [15:10] are not used and Bits [9:0] are used. The Bits [9:0] unsigned binary integer value represents the FB
voltage value with 2mV/LSB.
Equation 26 can be used to convert the 16Lu data (Bits [9:0] unsigned binary integer value, termed as COMMAND) reported in this
command to output voltage V_FB:
V_FB = 0.002  COMMAND
(EQ. 26)
According to Equation 2 on page 26, Equation 27 can be used to convert the 16Lu data (Bits [9:0] unsigned binary integer value,
termed as COMMAND) reported in this command to output voltage V_OUT, where R_FB2 and R_FB1 are resistor dividers from V_OUT to FB as
shown in Figure 4 on page 8:
V_OUT
=



1
+
RR_{-----FF----BB----21-}
 0.002  COMMAND
(EQ. 27)
Data Length in Bytes: 2
Data Format: 16Lu
Type: Read Only
Protectable: N/A
Default Value: N/A
Units: Volts (referred for V_FB with 2mV/LSB, use Equation 27 get V_OUT)
Equation: Equation 26 to calculate V_FB and Equation 27 to calculate V_OUT
Range: 0 to 2.046V (referred for V_FB with 2mV/LSB)
Example: READ_VOUT = 0800h = 800(decimal).
Use Equation 26 to get V_FB = 0.002 * 800 = 1.6V.
With R_FB1 = 4.53kΩ and R_FB2 = 97.6kΩ, use Equation 27 to get V_OUT = (1 + 97.6/4.53) * 0.002 * 800 = 36.072V.
COMMAND
Format
Bit Position
Access
Function
READ_VOUT (89h)
16Lu
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
See Following Table
Default Value
N/A
BIT NUMBER
9:0
15:10
MEANING
Reports the output voltage with value of the FB pin voltage with 2mV/LSB. Use Equation 26 to calculate V_FB, and
Equation 27 to calculate the corresponding V_OUT.
Not used
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FN8656.3
February 12, 2016