Calculation algorithm for recommended R1 & R2 values

Calculation algorithm for recommended R1 value

Here m denotes the supply voltage interpolation factor (used for supply voltage (VS) interpolation in range from VS(min) to VS(max), and n denotes the number of series (used for current interpolation (IPS) in range from 0 mA to IPS(max)):
Let m = 20 and n = 50
i ∈ { 0,1,2, ... , m }
j ∈ { 0,1,2, ... , n }

Power supply voltage (VS) interpolation:
VSi = VS(min) + ( ( VS(max) - VS(min) ) / m ) ⋅ i

Power shift current (IPS(max)) interpolation:
IPS(max)j = ( IPS(max) / n ) ⋅ j

Calculate R1 and R2 values for each series (for each value of IPS(max)): Calculate R1 values for each series (for each value of IPS(max)):
R2j = ( VGS_PWR_SH - VGS(typ) ) / IPS(max)j
R1j = ( VS(max) + VOVERHEAD - VOUT - max{ IOUT , IPS(max) } ⋅ RSHUNT - IPS(max)j ⋅ ( R2j + RDSON ) ) / IPS(max)j
R1j = ( VS(max) - VOUT - max{ IOUT , IPS(max) } ⋅ RSHUNT ) / IPS(max)j

Calculate IPSij, IOUTSij and PTLD1114ij for every combination of power supply voltage VSi and maximum power shift current IPS(max)j:
IPSij = 0 mA (if VSi - VOUT < VGS(typ))
IPSij = min{ ( VSi - VOUT - VGS(typ) ) / R2j , ( VSi - VOUT ) / ( R2j + R1j + RDSON ) } (otherwise if VSi - VOUT ≤ VGS_PWR_SH)
IPSij = min{ ( VGS_PWR_SH - VGS(typ) ) / R2j , ( VSi - VOUT ) / ( R2j + R1j + RDSON ) } (otherwise)
IPSij = ( VSi - VOUT ) / R1j
IOUTSij = max{ 0 mA ,  IOUT - IPSij }
PTLD1114ij = ( VSi - VOUT - RSHUNT ⋅ max{ IOUT , IPSij } ) ⋅ IOUTSij + RSHUNT ⋅ ( max{ IOUT , IPSij } )2

With the various R1 & R2 resistances calculated above the biggest resistances R1 & R2 are selected by comparing the maximum power dissipation over the given supply voltage range with the given maximum allowed power dissipation for the TLD1114 device. This resistances are then defined as the recommended resistances provided in the tool. With the various R1 resistances calculated above the biggest resistance R1 is selected by comparing the maximum power dissipation over the given supply voltage range with the given maximum allowed power dissipation for the TLD1114 device. This resistance is then defined as the recommended resistance provided in the tool.