HA16107P Datasheet, PDF (38/40 Pages) Hitachi Semiconductor – PWM Switching Regulator for High-performance Voltage Mode Control

HA16107P/FP, HA16108P/FP
This gate resistance R_G is given by the following equation.
R_G = (V_G/I_G) – (V_G × t_ON)/Qg, R_G = R_G1 + R_G2
I_G : Gate input peak current
V_G : Gate drive voltage wave high value (equal to power supply voltage of IC)
t_ON : Power MOS FET turn-on time
t_OFF : Power MOS FET turn-off time
Qg : Gate charge according to Figure 9
V_DS
V_DS
V_GS
(V)
(V)
V_GS
Qg (nc)
Figure 9 Power MOS FET Dynamic Input Characteristics
Refer to the power MOS FET catalog for information on t_ON and Qg.
By dividing R_G into R_G1 and R_G2, it is possible for speed to be slowed when the power MOS FET is on, and
increased when off.
Power MOS FET on and off times when mounted, t_ON’ and t_OFF’, are as follows.
t_ON’ = t_ON + Qg(R_G1 + R_G2)/V_G
t_OFF’ = t_OFF + Qg ⋅ R_G2/V_G
<Actual Example>
When driving a power MOS FET and 2SK1567 with an HA16107, etc.
(R_G1 = 100 Ω, R_G2 = 20 Ω, V_G = 15 V)
t_ON’ = 70 ns + 36 nc ⋅ (100 Ω + 20 Ω)/(15 V) = 360 (ns)
t_OFF’ = 135 ns + 36 nc ⋅ (20 Ω)/(15 V) = 183 (ns)
Generally, the gate resistance values in the case of this circuit configuration are on the order of 100 to 470 Ω for R_G1
and 10 to 47 Ω for R_G2.
Rev.4.00 Jun 15, 2005 page 38 of 39