IL6083_16 Datasheet, PDF (4/10 Pages) IK Semicon Co., Ltd – PWM Power Control IC with Interference Suppression

IL6083
Example for Oscillator
Frequency Calculation
Switching thresholds
V_T100 = High switching threshold (100% duty cycle)
V_T100 = V_S x α ₁ = (V_Batt - I_S x R₃) x α ₁
V_T<100 = High switching threshold (< 100% duty cycle)
V_T<100 = V_S x α₂ = (V_Batt - I_S x R₃) x α ₂
V_TL = Low switching threshold
V_TL = V_S x α ₃ = (V_Batt - I_S x R₃) x α ₃
where
α ₁, α ₂ and α ₃ are fixed values
Calculation Example
The above mentioned threshold voltages are calculated for the following values given in the data sheet.
VBatt = 12 V, IS = 4 mA, R3 = 150 Ω, α ₁ = 0.7, α ₂ = 0.67 and α ₃ = 0.28
VT100 = (12 V - 4 mA x 150 Ω) x 0.7 ≈ 8 V
VT<100 = 11.4 V x 0.67 = 7.6 V
VTL = 11.4 V x 0.28 = 3.2 V
Oscillator Frequency
3 cases have to be distinguished
1. f₁ for duty cycle = 100%, no slope reduction with capacitor C₄ (see Figure 4)
2. f2 for duty cycle < 100%, no slope reduction with capacitor C4 . For a duty cycle of less than 100%, the
oscillator frequency, f, is as follows:
3. f3 with duty cycle < 100% with slope reduction capacitor C4 (see “Output Slope Control”)
Electrical parameters are given for temperature range from minus 40 to + 110° С and V_batt. From 9 to 16,5V.
Operation is guaranteed for Vbatt from 6 to 9V. All electrical parameters are specified relatively to “common”
output (02).
By selecting different values of C2 and C4, it is possible to have a range of oscillator frequencies from 10 to
2000 Hz as shown in the data sheet.
Rev. 00