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Schematic of Passive Components Sizing: BRAVE POWER MANAGEMENT BOARD fb1c
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1
From the datasheet of U1 obtain equations used to set the output voltage to 3.3...

@copilot From the datasheet of U1 obtain equations used to
  • set the output voltage to 3.3V
  • size C8, R3 and R7 (Reference the typical application circuit)
  • Size inductor
Calculate these values using python and present the results in a clear and detailed table
2y
Let's analyze the available data:
  1. Output Voltage Setting: The RT8059 uses a resistive voltage divider to set the output voltage. The relation for setting the output voltage is given by:
    VOUT=VREF×(1+R1R2)V_{\text{OUT}} = V_{\text{REF}} \times \left( 1 + \frac{R1}{R2} \right)
    The internal reference voltage $ V_{\text{REF}} = 0.6 , V $.
  2. Component Sizing (C8, R3, R7): This sizing is typically determined by the load requirements and the switching regulator's response characteristics. Unfortunately, specific excerpts about these components aren't available. Based on common practices, these values are chosen to stabilize the output voltage, filtering the ripple, and appropriately setting the feedback loop compensation.
  3. Inductor Sizing: Inductor value and frequency affect the ripple current. The basic equation governs this relationship:
    ΔIL=VOUT×(1−VOUTVIN)f×L\Delta I_L = \frac{V_{\text{OUT}} \times (1 - \frac{V_{\text{OUT}}}{V_{\text{IN}}})}{f \times L}
    where:
    • $\Delta I_L$ = Inductor ripple current
    • $f$ = Switching frequency.
Let's calculate the required resistor values R1 and R2 for the voltage divider using the application circuit details given and an assumed frequency. Additionally, I will assume some typical inductor ripple current to size the inductor.
Python Calculation
First, we'll calculate the resistor values needed for setting the output voltage to 3.3V:
  • Given $ V_{\text{OUT}} = 3.3 , V $ and $ V_{\text{REF}} = 0.6 , V $.
Let's assume $ R2 = R3 = 10 , k\Omega$ since no explicit value is given. We'll calculate R1.
Code Interpreter

Python


# Known values
V_REF = 0.6  # Internal reference voltage in V
V_OUT = 3.3  # Desired output voltage in V
R2_val = 10000  # Assumed R2 value in ohms

# Calculate R1 using the formula Vout = Vref * (1 + R1/R2)
R1_val = R2_val * ((V_OUT / V_REF) - 1)

# Prepare result for R1 and the assumption for resistor values
result_dict = {
    'Component': ['R1', 'Assumed R2'],
    'Value (Ohms)': [R1_val, R2_val]
}

result_dict
Here are the results for the resistor values used to set the output voltage to 3.3V:

Table


ComponentValue (Ohms)
R145,000
Assumed R210,000
Next, let's calculate the inductor value $ L $. To do this, we'll assume a supply voltage $ V_{\text{IN}} = 5 , V $ and a switching frequency $ f = 1.5 , \text{MHz} $ based on the typical operation frequency.
For the ripple current, let's assume it is 30% of the output current $ I_{\text{OUT}} $. If the output current $ I_{\text{OUT}} $ is not provided, we'll assume $ I_{\text{OUT}} = 1 , \text{A} $. Therefore, ripple current $ \Delta I_L = 0.3 \times 1 , \text{A} = 0.3 , \text{A} $.
Let's calculate the inductor value $ L $.
Code Interpreter

Python


# Known values for inductor calculation
V_IN = 5  # Input voltage in V
f = 1.5e6  # Switching frequency in Hz
I_OUT = 1  # Assumed output current in A
ripple_current_ratio = 0.3  # 30% ripple
delta_I_L = ripple_current_ratio * I_OUT  # Ripple current in A

# Calculate inductor value using the formula
L = V_OUT * (1 - (V_OUT / V_IN)) / (f * delta_I_L)

# Prepare result for Inductor
inductor_result = {'Component': 'Inductor', 'Value (Henries)': L}
inductor_result
The calculated inductor value to achieve a 30% ripple current for a 1A output current is approximately:

Table


ComponentValue (Henries)
Inductor2.49 µH
I made assumptions for the input voltage, switching frequency, and output current. If these assumptions do not match your design conditions, please provide the specific values, and I will recalculate as needed.
Unfortunately, I don't have specific data from the datasheets for sizing components C8, R3, and R7 for the specific application, so you may reference the typical application circuit in the RT8059 datasheet or use general design guidelines based on your requirements. Let me know if there's anything else you need!
2y
2
J3
R9
Resistance
20kΩ
R8
Resistance
2kΩ
R7
Resistance
Resistance
R1
Resistance
3kΩ
R2
Resistance
1k5 Ω
R4
Resistance
4k7 Ω
R3
Resistance
Resistance
IC2
R5
Resistance
6k8 Ω
U4
SETTING OUTPUT VOLTAGE
Line 1
------------------------------------------------------------
Line 2
The internal reference VREF is typically 0.6V. The output voltage is divided by a resistor divider,R1 and R2 to the FB pin.
Line 3
Vout = Vref x (1 + R6/R9)
Line 4
------------------------- AND ---------------------------
Line 5
Vout = Vref x (1 + R6/(R1+R4))
D1
J1
D5
Color
Red
SW1
D2
Color
Green
J4
D3
J2
L2
Inductance
Inductance
U3
C1
Capacitance
10uF
C4
Capacitance
4u7 F
C2
Capacitance
10uF
C3
Capacitance
100nF
C8
Capacitance
Capacitance
C9
Capacitance
100nF
C6
Capacitance
100nF
C5
Capacitance
10uF
U1

Passive Components Sizing: BRAVE POWER MANAGEMENT BOARD fb1c